Water-soluble, hydrophobically associating copolymers having novel hydrophobically associating monomers

ABSTRACT

The present invention relates to water-soluble hydrophobically associating copolymers which are obtained in the presence of a nonpolymerizable surface-active compound and which comprise novel hydrophobically associating monomers. The monomers comprise an ethylenically unsaturated group and a polyether block, the polyether block comprising a hydrophilic polyethyleneoxy block and a hydrophobic polyalkyleneoxy block consisting of alkyleneoxy units having at least 4 carbon atoms. The monomers may optionally have a terminal polyethyleneoxy block. The invention further relates to processes for preparing the copolymers and to the use thereof.

The present invention relates to water-soluble hydrophobicallyassociating copolymers which are obtained in the presence of anonpolymerizable surface-active compound and which comprise novelhydrophobically associating monomers. The monomers comprise anethylenically unsaturated group and a polyether block, the polyetherblock comprising a hydrophilic polyethyleneoxy block and a hydrophobicpolyalkyleneoxy block consisting of alkyleneoxy units having at least 4carbon atoms. The monomers may optionally have a terminalpolyethyleneoxy block. The invention further relates to processes forpreparing the copolymers and to the use thereof.

Water-soluble thickening polymers are used in many fields of industry,for example in the cosmetics sector, in foods, for production ofcleaning products, printing inks and emulsion paints, and in mineral oilproduction.

Many chemically different classes of polymers usable as thickeners areknown. An important class of thickening polymers is that of what arecalled hydrophobically associating polymers. This is understood by thoseskilled in the art to mean water-soluble polymers having lateral orterminal hydrophobic groups, for example relatively long alkyl chains.In aqueous solution, such hydrophobic groups can associate withthemselves or with other substances having hydrophobic groups. Thisforms an associative network, which thickens the medium.

EP 705 854 A1, DE 100 37 629 A1 and DE 10 2004 032 304 A1 describewater-soluble hydrophobically associating copolymers and the usethereof, for example in the construction chemistry sector.

It is known that hydrophobically associating copolymers can be used inthe mineral oil production sector, especially for tertiary mineral oilproduction (enhanced oil recovery, EOR). Details of this are described,for example, in the review article by Taylor, K. C. and Nasr-El-Din, H.A. in J. Petr. Sci. Eng. 1998, 19, 265-280.

One of the techniques of tertiary mineral oil production is called“polymer flooding”. A mineral oil deposit is not an underground “sea ofmineral oil”; instead, the mineral oil is held in tiny pores in themineral oil-bearing rock. The diameter of the cavities in the formationis typically only a few micrometers. For polymer flooding, an aqueoussolution of a thickening polymer is injected through injection wellsinto a mineral oil deposit. The injection of the polymer solution forcesthe mineral oil through said cavities in the formation from theinjection well proceeding in the direction of the production well, andthe mineral oil is produced through the production well. It is importantfor this application that the aqueous polymer solution does not compriseany gel particles whatsoever. Even small gel particles having dimensionsin the micrometer range can block the fine pores in the formation andthus stop the mineral oil production. Hydrophobically associatingcopolymers for tertiary mineral oil production should therefore have aminimum proportion of gel particles.

A further technique in mineral oil production is called “hydraulicfracturing”. “Hydraulic fracturing” typically involves injecting ahigh-viscosity aqueous solution under high pressure into the oil- orgas-bearing formation stratum. The high pressure gives rise to cracks inthe rock, which facilitate the production of oil or gas. The thickenersused here are particularly guar and the more thermally stablederivatives thereof, for example hydroxypropyl guar or carboxymethylhydroxypropyl guar (J. K. Fink, Oil Field Chemicals, Elsevier 2003, p.240 ff). These biopolymers, however, like most polymers in general, havea distinct decrease in viscosity with rising temperature. Since,however, elevated temperatures prevail in the underground formations, itwould be advantageous for use in “hydraulic fracturing” to usethickeners whose viscosity does not decrease or even rises with risingtemperature.

Further fields of use of hydrophobically associating copolymers in thefield of mineral oil production is the thickening of drilling muds andcompletion fluids. This is described, for example, in the review articleTaylor, Ann. Transactions of the Nordic Rheology Society, Vol. 11, 2003.

WO 2010/133527 describes the preparation of hydrophobically associatingmonomers of theH₂C═C(R¹)—R⁴—O—(—CH₂—CH(R²)—O—)_(k)—(—CH₂—CH(R³)—O—)_(l)—R⁵ type and thesubsequent reaction with further hydrophilic monomers to givecopolymers. The macromonomers described have an ethylenicallyunsaturated group and a polyether group with block structure consistingof a hydrophilic polyalkyleneoxy block consisting essentially ofethyleneoxy units and of a terminal hydrophobic polyalkyleneoxy blockconsisting of alkyleneoxy units having at least 4 carbon atoms.

The document WO 2011/015520 describes the copolymerization ofhydrophobically associating monomers and monoethylenically unsaturatedhydrophilic monomers in the presence of nonionic surfactants and the useof the copolymers formed for polymer flooding.

CN 102146159 A likewise describes a process for preparing a polyvinylether monomer, the polyether monomer having the general formulaH₂C═C(R²)—O—R¹—O—(C_(a)H_(2a)O)_(n)—(C_(b)H_(2b)O)_(m)—H where a and bare each integers from 2 to 4, a does not equal b, and R¹ is aC₁-C₈-alkylene group. The monomers described in the document have apolyalkyleneoxy block formed from ethylene oxide, propylene oxide and/orbutylene oxide. The alkoxylation is preferably performed at atemperature in the range from 120 to 160° C. with addition of an alkyliccatalyst, for example potassium methoxide. For preparation of themonomers, the process according to WO 2010/133527 proceeds from suitablemonoethylenically unsaturated alcohols, which are subsequentlyalkoxylated in a two-stage process, such that the block structurementioned is obtained. Alkoxylation is effected first with ethyleneoxide, optionally in a mixture with propylene oxide and/or butyleneoxide, and, in a second step, with alkylene oxides having at least 4carbon atoms. The examples in WO 2010/133527 describe the performance ofthe alkoxylation using KOMe (potassium methoxide) as a catalyst at areaction temperature of 140° C., the concentration of potassium ionsbeing above 3 mol %.

The alkoxylation reaction is frequently performed under base catalysis.For this purpose, the alcohol used as the starting material is typicallyadmixed with alkali metal hydroxides or alkali metal alkoxides in apressure reactor and converted to the corresponding alkoxide.Subsequently, usually under inert gas atmosphere, the alkylene oxidesare metered in, for example in a plurality of steps. In order to controlthe reaction and avoid oversaturation of the reaction mixture withalkylene oxide, it is usually necessary to maintain particular pressureand temperature ranges in the alkoxylation.

The process according to WO 2010/133527 is said to avoid the formationof crosslinking by-products, and so the preparation of copolymers with alow gel content is said to be possible.

It has been found, however, that the prior art preparation processes donot constitute a reliable method for preparation of hydrophobicallyassociating copolymers with a low gel content. Fluctuating copolymerqualities have been found, for example in the event of variation ofpressure and reaction time in the alkoxylation steps, such thatsometimes highly crosslinked copolymer products have been obtained.

It has been found that, in prior art processes, monomers having twoethylenically unsaturated groups are probably formed as a by-product.These bifunctional by-products have a crosslinking effect and lead toincreased gel formation in the copolymerization. It has been found thatoccurrence of these unwanted side reactions increases with temperatureand duration of the reaction. Copolymers with a gel content aregenerally no longer filterable and no longer usable for injection intoporous matrices in mineral oil deposits.

There is typically a preference for KOMe (potassium methoxide) as abasic catalyst over NaOMe (sodium methoxide), since KOMe is morestrongly basic than NaOMe, and therefore the alkoxylation reactionproceeds more quickly. It has been found, however, that the morestrongly basic KOMe promotes the formation of the above-describedcrosslinking monomers. Butylene oxide and pentylene oxide react muchmore slowly than ethylene oxide or propylene oxide; therefore, the sidereactions in the case of alkoxylation with butylene oxide or pentyleneoxide have a more distinct effect.

It was therefore an object of the invention to provide hydrophobicallyassociating copolymers with lower or undetectable gel contents comparedto the already known copolymers, proceeding from novel, crosslinker-freemonomers. The copolymers were also to be preparable more economicallythan to date, and the action thereof as thickeners was to be at leastequal compared to the existing compounds.

It has now been found that, surprisingly, the formation of crosslinkingbifunctional compounds and hence the gel content in the resultingcopolymers can be reduced or virtually completely avoided when acritical amount of potassium ions less than or equal to 0.9 mol % basedon the alcohol to be alkoxylated and a temperature less than or equal to135° C. is observed in the second alkoxylation step (reaction withbutylene oxide or pentylene oxide). It has additionally been found thatthe preparation process according to the invention, with the givensafety demands relating to chemistry and operation (more particularly apressure less than 2.1 bar in the alkoxylation with pentylene oxide andmore particularly a pressure of less than 3.1 bar in the alkoxylationwith butylene oxide), ensures good reproducibility with reasonablereaction time.

Accordingly, water-soluble hydrophobically associating copolymerscomprising the following monomers have been found:

-   (a) 0.1 to 20% by weight of at least one hydrophobically associating    monomer (a), and-   (b) 25 to 99.9% by weight of at least one hydrophilic monomer (b)    other than monomer (a),    -   with use of at least one further, nonpolymerizable        surface-active component (c) in the course of synthesis thereof,        prior to the initiation of the polymerization reaction,    -   where the stated amounts are each based on the total amount of        all monomers in the copolymer, and at least one of the        monomers (a) being a monomer of the general formula (I)

H₂C═C(R¹)—R²—O—(—CH₂—CH₂—O—)_(k)—(—CH₂—CH(R³)—O—)_(l)—(—CH₂—CH₂—O—)_(m)—R⁴  (I)

-   -   where the —(—CH₂—CH₂—O—)_(k), —(—CH₂—CH(R³)—O—)_(l) and        optionally —(—CH₂—CH₂—O—)_(m) units are arranged in block        structure in the sequence shown in formula (I)    -   and the radicals and indices are each defined as follows:    -   k: is a number from 15 to 35, preferably from 20 to 28, more        preferably from 23 to 26;    -   l: is a number from 5 to 30, preferably from 5 to 28, preferably        from 5 to 25;    -   m: is a number from 0 to 15, preferably from 0 to 10;    -   R¹: is H or methyl;    -   R²: is independently a single bond or a divalent linking group        selected from the group of —(C_(n)H_(2n))— and        —O—(C_(n′)H_(2n′))—, where n is a natural number from 1 to 6 and        n′ is a natural number from 2 to 6,    -   R³: is independently a hydrocarbyl radical having at least 2        carbon atoms or an ether group of the general formula        —CH₂—O—R^(3′) where R^(3′) is a hydrocarbyl radical having at        least 2 carbon atoms; with the proviso that the sum total of the        carbon atoms in all hydrocarbyl radicals R³ or R^(3′) is in the        range from 15 to 60, preferably from 15 to 56, preferably from        15 to 50,    -   R⁴: is independently H or a hydrocarbyl radical having 1 to 4        carbon atoms;    -   and the hydrophobically associating monomer (a) of the general        formula (I) being obtainable by a process comprising the        following steps:

-   a) reacting a monoethylenically unsaturated alcohol A1 of the    general formula (II)

H₂C═C(R¹)—R²—OH  (II)

-   -   with ethylene oxide,    -   where the R¹ and R² radicals are each as defined above;    -   with addition of an alkaline catalyst C1 comprising KOMe and/or        NaOMe to obtain an alkoxylated alcohol A2;

-   b) reacting the alkoxylated alcohol A2 with at least one alkylene    oxide Z of the formula (Z)

-   -   where R³ is as defined above;    -   with addition of an alkaline catalyst C2;    -   where the concentration of potassium ions in the reaction in        step b) is less than or equal to 0.9 mol %, preferably from 0.01        to 0.9 mol %, more preferably 0.01 to 0.5 mol %, based on the        alcohol A2 used;    -   and where the reaction in step b) is performed at a temperature        less than or equal to 135° C.,    -   to obtain an alkoxylated alcohol A3 of the formula (III)

H₂C═C(R¹)—R²—O—(—CH₂—CH₂—O—)_(k)—(—CH₂—CH(R³)—O—)_(l)—R⁴  (III)

-   -   where R⁴=H, where the R¹, R² and R³ radicals and the indices k        and l are each as defined above;

-   c) optionally reacting at least a portion of the alkoxylated alcohol    A3 with ethylene oxide to obtain the alkoxylated alcohol A4    corresponding to the monomer (a) of the formula (I) where R⁴=H and    m>0;

-   d) optionally etherifying the alkoxylated alcohol A3 and/or A4 with    a compound

R₄—X

-   -   where R⁴ is as defined above and X is a leaving group,        preferably selected from the group of Cl, Br, I, —O—S₂—CH₃        (mesylate), —O—SO₂—CF₃ (triflate) and —O—SO₂—OR⁴    -   to obtain a monomer (a) of the formula (I) and/or (III) where        R⁴=hydrocarbyl radical having 1 to 4 carbon atoms.

In a preferred embodiment the invention relates to water-solublehydrophobically associating copolymers, wherein the radicals and indicesin monomers (a) of formula (I) are each defined as follows:

-   -   k: is a number from 23 to 26;    -   l: is a number from 5 to 30, preferably from 5 to 28, preferably        from 5 to 25;    -   m: is a number from 0 to 15, preferably from 0 to 10;    -   R¹: is H or methyl;    -   R²: is independently a single bond or a divalent linking group        selected from the group of —(C_(n)H_(2n))— and        —O—(C_(n′)H_(2n′))—, where n is a natural number from 1 to 6 and        n′ is a natural number from 2 to 6,    -   R³: is independently a hydrocarbyl radical having at least 2        carbon atoms or an ether group of the general formula        —CH₂—O—R^(3′) where R^(3′) is a hydrocarbyl radical having at        least 2 carbon atoms; with the proviso that the sum total of the        carbon atoms in all hydrocarbyl radicals R³ or R^(3′) is in the        range from 15 to 60, preferably from 15 to 56, preferably from        15 to 50;    -   R⁴: is independently H or a hydrocarbyl radical having 1 to 4        carbon atoms.

In a preferred embodiment, the sum total of all monomers in thecopolymer is 100% by weight.

The monomer a) is preferably exclusively a monomer of the generalformula (I) as described above.

In a preferred embodiment water-soluble hydrophobically associatingcopolymers comprising the following monomers have been found:

-   (c) 0.1 to 20% by weight of at least one hydrophobically associating    monomer (a), and-   (d) 25 to 99.9% by weight of at least one hydrophilic monomer (b)    other than monomer (a),    -   with use of at least one further, nonpolymerizable        surface-active component (c) in the course of synthesis thereof,        prior to the initiation of the polymerization reaction,    -   where the stated amounts are each based on the total amount of        all monomers in the copolymer, and at least one of the        monomers (a) being a monomer of the general formula (I)

H₂C═C(R¹)—R²—O—(—CH₂—CH₂—O—)_(k)—(—CH₂—CH(R³)—O—)_(l)—(—CH₂—CH₂—O—)_(m)—R⁴  (I)

-   -   where the —(—CH₂—CH₂—O—)_(k), —(—CH₂—CH(R³)—O—)₃ and optionally        —(—CH₂—CH₂—O—)_(m) units are arranged in block structure in the        sequence shown in formula (I)    -   and the radicals and indices are each defined as follows:    -   k: is a number from 23 to 26;

l: is a number from 8.5 to 17.25;

-   -   m: is a number from 0 to 15, preferably from 0 to 10;    -   R¹: is H or methyl;    -   R²; is independently a single bond or a divalent linking group        selected from the group of —(C_(n)H_(2n))— and        —O—(C_(n′)H_(2n′))—, where n is a natural number from 1 to 6 and        n′ is a natural number from 2 to 6,    -   R³: is independently a hydrocarbyl radical having at least 2        carbon atoms or an ether group of the general formula        —CH₂—O—R^(3′) where R^(3′) is a hydrocarbyl radical having at        least 2 carbon atoms; with the proviso that the sum total of the        carbon atoms in all hydrocarbyl radicals R³ or R^(3′) is in the        range from 25.5 to 34.5,    -   R⁴: is independently H or a hydrocarbyl radical having 1 to 4        carbon atoms;    -   and the hydrophobically associating monomer (a) of the general        formula (I) being obtainable by a process comprising the        following steps:

-   a) reacting a monoethylenically unsaturated alcohol A1 of the    general formula (II)

H₂C═C(R¹)—R²—OH  (II)

-   -   with ethylene oxide,    -   where the R¹ and R² radicals are each as defined above;    -   with addition of an alkaline catalyst C1 comprising KOMe and/or        NaOMe to obtain an alkoxylated alcohol A2;

-   b) reacting the alkoxylated alcohol A2 with at least one alkylene    oxide Z of the formula (Z)

-   -   where R³ is as defined above;    -   with addition of an alkaline catalyst C2;    -   where the concentration of potassium ions in the reaction in        step b) is less than or equal to 0.9 mol %, preferably from 0.01        to 0.9 mol %, more preferably 0.01 to 0.5 mol %, based on the        alcohol A2 used;    -   and where the reaction in step b) is performed at a temperature        less than or equal to 135° C.,    -   to obtain an alkoxylated alcohol A3 of the formula (III)

H₂C═C(R¹)—R²—O—(—CH₂—CH₂—O—)_(k)—(—CH₂—CH(R³)—O—)_(l)—R⁴  (III)

-   -   where R⁴=H, where the R¹, R² and R³ radicals and the indices k        and l are each as defined above;

-   c) optionally reacting at least a portion of the alkoxylated alcohol    A3 with ethylene oxide to obtain the alkoxylated alcohol A4    corresponding to the monomer (a) of the formula (I) where R⁴=H and    m>0;

-   d) optionally etherifying the alkoxylated alcohol A3 and/or A4 with    a compound

R₄—X

-   -   where R⁴ is as defined above and X is a leaving group,        preferably selected from the group of Cl, Br, I, —O—SO₂—CH₃        (mesylate), —O—SO₂—CF₃ (triflate) and —O—SO₂—OR⁴    -   to obtain a monomer (a) of the formula (I) and/or (III) where        R⁴=hydrocarbyl radical having 1 to 4 carbon atoms.

In a preferred embodiment, the sum total of all monomers in thecopolymer is 100% by weight.

The monomer a) is preferably exclusively a monomer of the generalformula (I) as described above.

In addition, the preparation of such copolymers has been found, as hasthe use thereof for development, exploitation and completion ofunderground mineral oil and natural gas deposits.

Specific details of the invention are as follows:

The inventive hydrophobically associating copolymers are water-solublecopolymers having hydrophobic groups. In aqueous solution, thehydrophobic groups can associate with themselves or with the hydrophobicgroups of other substances, and thicken the aqueous medium as a resultof these interactions.

The person skilled in the art is aware that the solubility ofhydrophobically associating (co)polymers in water may be more or lessstrongly dependent on the pH, depending on the nature of the monomersused. The reference point for the assessment of water solubility willtherefore in each case be the pH desired for the respective end use ofthe copolymer.

Monomer (a)

The inventive hydrophobically associating copolymer comprises at leastone monoethylenically unsaturated monomer (a) which impartshydrophobically associating properties to the inventive copolymer and istherefore referred to hereinafter as hydrophobically associatingmonomer.

According to the invention, at least one of the hydrophobicallyassociating monomers (a) is a monomer of the general formula (I)

H₂C═C(R¹)—R²—O—(—CH₂—CH₂—O—)_(k)—(—CH₂—CH(R³)—O—)_(l)—(—CH₂—CH₂—O—)_(m)—R⁴  (I).

In the monomers (a) of the general formula (I), an ethylenic groupH₂C═C(R¹)— is bonded via a divalent linking group —R²—O— to apolyalkyleneoxy radical having block structure—(—CH₂—CH₂—O—)_(k)—(—CH₂—CH(R³)—O—)_(l)—R⁴, where the blocks—(—CH₂—CH₂—O—)_(k) and —(—CH₂—CH(R³)—O—)_(l) are arranged in thesequence shown in formula (I). Optionally, the monomer (a) of theformula (I) may have a further polyethyleneoxy block —(—CH₂—CH₂—O—)_(m).The polyalkyleneoxy radical has either a terminal OH group or a terminalether group OR⁴.

In the abovementioned formula, R¹ is H or a methyl group. Preferably, R¹is H.

R² is a single bond or a divalent linking group selected from the groupof —(C_(n)H_(2n))— and —O—(C_(n′)H_(2n′))—. In the formulae mentioned, nis a natural number from 1 to 6 and n′ a natural number from 2 to 6. Inother words, the linking group comprises straight-chain or branchedaliphatic hydrocarbyl groups which have 1 to 6 carbon atoms or 2 to 6carbon atoms and are joined either directly or via an ether group —O— tothe ethylenic group H₂C═C(R¹)—. The —(C_(n)H_(2n))—, and—(C_(n′)H_(2n′)) groups are preferably linear aliphatic hydrocarbylgroups.

Preferably, the R² group=—(C_(n)H_(2n))— is a group selected from —CH₂—,—CH₂—CH₂— and —CH₂—CH₂—CH₂—, particular preference being given to amethylene group —CH₂—.

Preferably, the R² group=—O—(C_(n′)H_(2n′))— is a group selected from—O—CH₂—CH₂—, —O—CH₂—CH₂—CH₂— and —O—CH₂—CH₂—CH₂—CH₂—, particularpreference being given to —O—CH₂—CH₂—CH₂—CH₂—.

More preferably, the R² group is a —O—(C_(n′)H_(2n′))— group.

In addition, R² is more preferably a group selected from —CH₂— and—O—CH₂—CH₂—CH₂—CH₂—, very particular preference being given to—O—CH₂—CH₂—CH₂—CH₂—.

The monomers (a) additionally have a polyalkyleneoxy radical consistingof the units —(—CH₂—CH₂—O—)_(k), —(—CH₂—CH(R³)—O—)_(l) and optionally—(—CH₂—CH₂—O—)_(m), the units being arranged in block structure in thesequence shown in formula (I). The transition between the blocks may beabrupt or else continuous.

The number of ethyleneoxy units k is a number from 15 to 35, preferablyfrom 20 to 28, more preferably from 23 to 26.

Preferably, the number of ethyleneoxy units k is a number from 23 to 26.It will be apparent to the person skilled in the art in the field ofpolyalkylene oxides that the numbers mentioned are mean values ofdistributions.

In the second block —(—CH₂—CH(R³)—O—)_(l)—, the R³ radicals are eachindependently hydrocarbyl radicals having at least 2 carbon atoms,preferably having 2 to 14 carbon atoms, preferably 2 to 4, and morepreferably having 2 or 3 carbon atoms. This may be an aliphatic and/oraromatic, linear or branched carbon radical. Preference is given toaliphatic radicals. Particular preference is given to an aliphaticunbranched hydrocarbyl radical having 2 or 3 carbon atoms. The blockmentioned is preferably a polybutyleneoxy block or a polypentyleneoxyblock.

Examples of suitable R³ radicals comprise ethyl, n-propyl, n-butyl,n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-dodecyl,n-tetradecyl, and phenyl.

Examples of suitable R³ radicals comprise ethyl, n-propyl, n-butyl,n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl or n-decyl and phenyl.Examples of preferred radicals comprise n-propyl, n-butyl, n-pentyl,particular preference being given to an ethyl radical or an n-propylradical.

The R³ radicals may additionally be ether groups of the general formula—CH₂—O—R^(3′) where R^(3′) is an aliphatic and/or aromatic, linear orbranched hydrocarbyl radical having at least 2 carbon atoms, preferably2 to 10 carbon atoms and more preferably at least 3 carbon atoms.Examples of R^(3′) radicals comprise n-propyl, n-butyl, n-pentyl,n-hexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or phenyl.

Examples of R^(3′) radicals comprise n-propyl, n-butyl, n-pentyl,n-hexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-dodecyl,n-tetradecyl or phenyl.

The block —(—CH₂—CH(R³)—O—)_(l)— is thus a block which consists ofalkyleneoxy units having at least 4 carbon atoms, preferably having 4 or5 carbon atoms, and/or glycidyl ethers having an ether group of at least2, preferably at least 3, carbon atoms. Preferred R³ radicals are thehydrocarbyl radicals mentioned; the units in the second block are morepreferably alkyleneoxy units comprising at least 4 carbon atoms, such asbutyleneoxy and pentyleneoxy units or units of higher alkylene oxides,most preferably butylene oxide or pentyleneoxy units.

It will be apparent to the person skilled in the art in the field ofpolyalkylene oxides that the orientation of the hydrocarbyl radicals R³may depend on the conditions in the alkoxylation, for example on thecatalyst selected for the alkoxylation. The alkyleneoxy groups can thusbe incorporated into the monomer in the orientation —(—CH₂—CH(R³)—O—)—or else the inverse orientation —(—CH(R³)—CH₂—O—)_(l)—. Therepresentation in formula (I) shall therefore not be regarded as beingrestricted to a particular orientation of the R³ group.

The number of alkyleneoxy units l is a number from 5 to 30, preferablyfrom 5 to 28, preferably from 5 to 25, preferably from 7 to 23,preferably from 7 to 18, especially preferably from 8.5 to 17.25 withthe proviso that the sum total of the carbon atoms in all hydrocarbylradicals R³ or R^(3′) is in the range from 15 to 60, preferably from 15to 56, preferably 15 to 50, preferably from 25.5 to 34.5. If the R³radicals are an ether group —CH₂—O—R^(3′), the proviso applies that thesum total of the hydrocarbyl radicals R^(3′) is in the range from 15 to60, preferably from 15 to 56, preferably from 15 to 50, more preferredfrom 25.5 to 34.5, not including the carbon atom in the linking —CH₂—O—group in —CH₂—O—R^(3′).

A preferred embodiment relates to an above-described copolymercomprising a monomer (a) where R³ is ethyl and l is a number from 7.5 to28, preferably from 7.5 to 25, more preferably from 12.75 to 25,especially preferably from 13 to 23, especially preferably from 12.75 to17.25, for example 14, 16 or 22.

In a preferred embodiment the number of alkyleneoxy units l is a numberfrom 8.5 to 17.25, with the proviso that the sum total of the carbonatoms in all hydrocarbyl radicals R³ or R^(3′) is in the range from 25.5to 34.5. If the R³ radicals are an ether group —CH₂—O—R^(3′), theproviso applies that the sum total of the hydrocarbyl radicals R^(3′) isin the range from 25.5 to 34.5, not including the carbon atom in thelinking —CH₂—O— group in —CH₂—O—R^(3′). A preferred embodiment relatesto an above-described copolymer comprising a monomer (a) where R³ isethyl and l is a number from 12.75 to 17.25, especially 13 to 17, forexample 14 or 16. A further preferred embodiment relates to anabove-described copolymer comprising a monomer (a) where R³ is n-propyland l is a number from 8.5 to 11.5, preferably 9 to 11, for example 10or 11. It will be apparent to the person skilled in the art in the fieldof polyalkylene oxides that the numbers mentioned are mean values ofdistributions.

The optional block —(—CH₂—CH₂—O—)_(m) is a polyethyleneoxy block. Thenumber of ethyleneoxy units m is a number from 0 to 15, preferably from0 to 10, more preferably 0.1 to 10, more preferably 0.1 to 5, especiallypreferably 0.5 to 5 and most preferably 0.5 to 2.5. It will be apparentto the person skilled in the art in the field of polyalkylene oxidesthat the numbers mentioned are mean values of distributions.

In a preferred embodiment of the invention, m is greater than 0 (i.e.the optional step c) is executed). In particular in this embodiment m isa number from 0.1 to 15, preferably from 0.1 to 10, more preferably from0.5 to 10, especially preferably from 1 to 7, further preferably from 2to 5. It will be apparent to the person skilled in the art in the fieldof polyalkylene oxides that the numbers mentioned are mean values ofdistributions.

The R⁴ radical is H or a preferably aliphatic hydrocarbyl radical having1 to 4 carbon atoms. R⁴ is preferably H, methyl or ethyl, morepreferably H or methyl and most preferably H.

In the monomers of the formula (I), a terminal, monoethylenic group isthus joined to a polyalkyleneoxy group with block structure, morespecifically first to a hydrophilic block having polyethyleneoxy unitsand the latter in turn to a second hydrophobic block formed fromalkyleneoxy units, preferably at least butyleneoxy units or units ofhigher alkylene oxides and more preferably from butyleneoxy orpentyleneoxy units. The second block may have a terminal —OR⁴ group,especially an OH group. The end group need not be etherified with ahydrocarbyl radical for hydrophobic association; instead, the secondblock —(—CH₂—CH(R³)—O—)_(l) itself having the R³ or R^(3′) radicals isresponsible for the hydrophobic association of the copolymers preparedusing the monomers (a). Etherification is just one option which can beselected by the person skilled in the art according to the desiredproperties of the copolymer.

It will be apparent to the person skilled in the art in the field ofpolyalkyleneoxy block copolymers that the transition between the twoblocks, according to the method of preparation, may be abrupt or elsecontinuous. In the case of a continuous transition, there is atransition zone comprising monomers of both blocks between the blocks.If the block boundary is fixed in the middle of the transition zone, thefirst block —(—CH₂—CH₂—O—)_(k) may correspondingly still have smallamounts of —(—CH₂—CH(R³)—O—)— units and the second block—(—CH₂—CH(R³)—O—)_(l) small amounts of —(—CH₂—CH₂—O—)— units, in whichcase these units, however, are not distributed randomly over the blockbut are arranged within the transition zone mentioned. Moreparticularly, the optional third block (—CH₂—CH₂—O—)_(m) may have smallamounts of units —(—CH₂—CH(R³)—O—)—.

The present invention relates to a process for preparing a macromonomerM of the formula (I) where the (—CH₂—CH₂—O—)_(k) and(—CH₂—CH(R³)—O—)_(l) and optionally —(—CH₂—CH₂—O—)_(m) units arearranged in block structure in the sequence shown in formula (I). “Blockstructure” in the context of the present invention means that the blocksare formed from the corresponding units to an extent of at least 85 mol%, preferably to an extent of at least 90 mol %, more preferably to anextent of at least 95 mol %, based on the total amount of the respectiveblock. This means that the blocks, as well as the corresponding units,may have small amounts of other units (especially other polyalkyleneoxyunits). More particularly, the optional polyethyleneoxy block—(—CH₂—CH₂—O—)_(m) comprises at least 85 mol %, preferably at least 90mol %, based on the total amount of the block, the unit (—CH₂—CH₂—O—).More particularly, the optional polyethyleneoxy block —(—CH₂—CH₂—O—)_(m)consists of 85 to 95 mol % of the unit (—CH₂—CH₂—O—) and of 5 to 15 mol% of the unit (—CH₂—CH(R³)—O—).

The invention preferably relates to a copolymer in which the radicalsand indices are each defined as follows:

k: is a number from 15 to 35, preferably from 20 to 28, preferably from23 to 26;l: is a number from 5 to 30, preferably from 5 to 28, preferably from 5to 25;m: is a number from 0 to 15, preferably 0 or preferably from 0.5 to 10;

R¹: is H;

R²: is a divalent linking group —O—(C_(n′)H_(2n′))— where n′ is 4;R³: is independently a hydrocarbyl radical having 2 carbon atoms,especially ethyl;

R⁴: is H.

The invention preferably relates to a copolymer in which the radicalsand indices are each defined as follows:

k: is a number from 15 to 35, preferably from 20 to 28, preferably from23 to 26;l: is a number from 5 to 30, preferably from 5 to 28, preferably from 5to 25;m: is a number from 0.1 to 10, preferably from 0.5 to 10, especiallypreferably from 2 to 5;

R¹: is H;

R²: is a divalent linking group —O—(C_(n′)H_(2n′))— where n′ is 4;R³: is independently a hydrocarbyl radical having 2 carbon atoms,especially ethyl;

R⁴: is H.

The invention preferably relates to a copolymer in which the radicalsand indices are each defined as follows:

-   k: is a number from 15 to 35, preferably from 20 to 28, preferably    from 23 to 26;-   l: is a number from 7.5 to 28, preferably from 7.5 to 25, more    preferably from 12.75 to 25; especially preferably from 13 to 23,    for example 14, 16 or 22;-   m: is a number from 0 to 15, preferably 0 or preferably 0.5 to 10;-   R¹: is H;-   R²: is a divalent linking group —O—(C_(n′)H_(2n′))— where n′ is 4;-   R³: is independently a hydrocarbyl radical having 2 carbon atoms,    especially ethyl;-   R⁴: is H.

The invention preferably relates to a copolymer in which the radicalsand indices are each defined as follows:

-   k: is a number from 15 to 35, preferably from 20 to 28, preferably    from 23 to 26;-   l: is a number from 7.5 to 28, preferably from 7.5 to 25, more    preferably from 12.75 to 25; especially preferably from 13 to 23,    for example 14, 16 or 22;-   m: is a number from 0.1 to 10, preferably from 0.5 to 10, more    preferably from 2 to 5;-   R¹: is H;-   R²: is a divalent linking group —O—(C_(n′)H_(2n′))— where n′ is 4;-   R³: is independently a hydrocarbyl radical having 2 carbon atoms,    especially ethyl;-   R⁴: is H.

The invention preferably relates to a copolymer in which the radicalsand indices are each defined as follows:

k: is a number from 23 to 26;l: is a number from 12.75 to 17.25;m: is a number from 0 to 15, preferably 0 or preferably 0.5 to 10;

R¹: is H;

R²: is a divalent linking group —O—(C_(n′)H_(2n′))— where n′ is 4;R³: is independently a hydrocarbyl radical having 2 carbon atoms,especially ethyl;

R⁴: is H.

In addition, the invention preferably relates to a copolymer in whichthe radicals and indices are each defined as follows:

k: is a number from 23 to 26;l: is a number from 8.5 to 11.5;m: is a number from 0 to 15, preferably 0 to 10; preferably 0 orpreferably 0.5 to 10;

R¹: is H;

R²: is a divalent linking group —O—(C_(n′)H_(2n′))— where n′ is 4;R³: is a hydrocarbyl radical having 3 carbon atoms, especially n-propyl;

R⁴: is H.

In addition, the invention preferably relates to a copolymer in whichthe monomer (a) of the formula (I) is a mixture of a monomer (a) of theformula (I) where m=0 and a monomer (a) of the formula (I) where m=1 to15, preferably 1 to 10. In addition, the invention preferably relates toa copolymer in which the weight ratio of the monomer (a) of the formula(I) where m=0 and the monomer (a) of the formula (I) where m=1 to 15,preferably 1 to 10, is in the range from 19:1 to 1:19, preferably in therange from 9:1 to 1:9. This mixture of monomer (a) of the formula (I)where m=0 and monomer (a) of the formula (I) where m=1 to 15 morepreferably gives rise to a mean value (averaged over all monomers (a) inthe mixture) in the range from m=0.1 to 10, preferably from 0.1 to 5,more preferably from 0.5 to 5, more preferably from 0.5 to 2.5.

Further, this mixture of monomer (a) of the formula (I) where m=0 andmonomer (a) of the formula (I) where m=1 to 15 more preferably givesrise to a mean value (averaged over all monomers (a) in the mixture) inthe range from m=0.1 to 10, preferably from 0.1 to 5, more preferablyfrom 0.5 to 5, more preferably from 0.5 to 3.5, more preferably from 0.5to 2.5.

In general, an ethoxylation of the alkoxylated alcohol A3 in step c)will be effected preferentially on already ethoxylated chains, since theprimary alkoxide group is more active compared to the secondary alkoxidegroup of the alcohol A3. Thus, more particularly, after step c), theremay be a mixture of chains having a terminal ethyleneoxy block—(—CH₂—CH₂—O—)_(m) comprising at least one unit (monomers of the formula(I)), and chains which do not have a terminal ethyleneoxy block—(—CH₂—CH₂—O—)_(m) (monomers of the formula (III)).

Preparation of the Monomers (a) of the Formula (I)

The monomers (a) of the general formula (I)

H₂C═C(R¹)—R²—O—(—CH₂—CH₂—O—)_(k)—(—CH₂—CH(R³)—O—)_(l)—(—CH₂—CH₂—O—)_(m)—R⁴  (I)

are prepared in the steps described above. The preferred embodiments ofmonomer (a) correspond to those already specified above.

Step a) of the process according to the invention comprises the reactionof a monoethylenically unsaturated alcohol A1 with ethylene oxide, withaddition of an alkaline catalyst C1 comprising KOMe (potassiummethoxide) and/or NaOMe (sodium methoxide), to obtain an alkoxylatedalcohol A2.

The preferred conditions specified hereinafter (for example pressureand/or temperature ranges) in the reactions in step a), b), c) and/or d)mean that the respective step is performed wholly or partly under thegiven conditions.

Step a) preferably first comprises the reaction of the monoethylenicallyunsaturated alcohol A1 with the alkaline catalyst C1. Typically, thealcohol A1 used as the starting material for this purpose is admixed ina pressure reactor with an alkaline catalyst C1. Reduced pressure oftypically less than 100 mbar, preferably in the range from 50 to 100mbar and/or temperature elevated typically to 30 to 150° C. allow waterand/or low boilers still present in the mixture to be drawn off.Thereafter, the alcohol is present essentially in the form of thecorresponding alkoxide. Subsequently, the reaction mixture is typicallytreated with inert gas (e.g. nitrogen).

Step a) also preferably first comprises the reaction of themonoethylenically unsaturated alcohol A1 with the alkaline catalyst C1.Typically, the alcohol A1 used as the starting material for this purposeis admixed in a pressure reactor with an alkaline catalyst C1. Reducedpressure of typically less than 100 mbar, preferably in the range from30 to 100 mbar and/or temperature elevated typically to 30 to 150° C.allow water and/or low boilers still present in the mixture to be drawnoff. Thereafter, the alcohol is present essentially in the form of thecorresponding alkoxide. Subsequently, the reaction mixture is typicallytreated with inert gas (e.g. nitrogen).

Step a) preferably comprises the addition of ethylene oxide to theabove-described mixture of alcohol A1 with the alkaline catalyst C1 (asdescribed above). After the addition of ethylene oxide has ended, thereaction mixture is typically allowed to react further. The additionand/or further reaction is effected typically over a period of 2 to 36h, preferably of 5 to 24 h, especially preferably of 5 to 15 h, morepreferably of 5 to 10 h.

Step a) preferably comprises the addition of ethylene oxide to theabove-described mixture of alcohol A1 with the alkaline catalyst C1 (asdescribed above). After the addition of ethylene oxide has ended, thereaction mixture is typically allowed to react further. The furtherreaction is typically effected over a period of 0.1 to 1 h. The additionincluding optional decompression (intermediate reduction of the pressurefor example from 6 to 3 bar absolute) and including further reaction iseffected for example over a period of 2 to 36 h, preferably of 5 to 24h, especially preferably of 5 to 15 h, more preferably of 5 to 10 h.

Step a) is effected typically at temperatures of 60 to 180° C.,preferably of 130 to 150° C., more preferably of 140 to 150° C. Moreparticularly, step a) comprises the addition of ethylene oxide to themixture of alcohol A1 with the alkaline catalyst C1 at a temperature of60 to 180° C., preferably of 130 to 150° C., more preferably of 140 to150° C.

The ethylene oxide is preferably added to the mixture of alcohol A1 andalkaline catalyst C1 at a pressure in the range from 1 to 7 bar,preferably in the range from 1 to 5 bar. In order to satisfy the safetyregulations, the addition in step a) is typically performed at apressure in the range from 1 to 3.1 bar. More particularly, the additionof ethylene oxide and/or the further reaction are performed under theabovementioned conditions.

The ethylene oxide is preferably added to the mixture of alcohol A1 andalkaline catalyst C1 at a pressure in the range from 1 to 7 bar,preferably in the range from 1 to 6 bar. In order to satisfy the safetyregulations, the addition in step a) is typically performed at apressure in the range from 1 to 4 bar, preferably from 1 to 3.9 bar,more preferably from 1 to 3.1 bar or in a further embodiment of theinvention from 3 to 6 bar. More particularly, the addition of ethyleneoxide and/or the further reaction are performed under the abovementionedconditions.

Step a) preferably comprises the addition of ethylene oxide to a mixtureof alcohol A1 and alkaline catalyst C1 over a period of less than orequal to 36 h, preferably less than or equal to 32 h, more preferablyover a period of 2 to 32 h, and at a pressure of less than or equal to 5bar, preferably at 1 to 3.1 bar. More particularly, the above-specifiedperiod comprises the addition of ethylene oxide and/or the furtherreaction.

Step a) preferably comprises the addition of ethylene oxide to a mixtureof alcohol A1 and alkaline catalyst C1 over a period of less than orequal to 36 h, preferably less than or equal to 32 h, more preferablyover a period of 2 to 32 h, and at a pressure of less than or equal to 5bar, preferably less than 1 to 4 bar, especially preferably at 1 to 3.9bar, preferably at 1 to 3.1 bar. More particularly, the above-specifiedperiod comprises the addition of ethylene oxide and/or the furtherreaction.

More particularly, the reaction of a monoethylenically unsaturatedalcohol A1 with ethylene oxide, with addition of an alkaline catalyst C1comprising KOMe (potassium methoxide) and/or NaOMe (sodium methoxide),in step a) of the process according to the invention can be effected inone or more ethoxylation steps. Preference is given to a process asdescribed above wherein step a) comprises the following steps:

-   -   reaction of the monoethylenically unsaturated alcohol A1 with        the alkaline catalyst C1, reaction of the mixture of alcohol A1        and catalyst C1 with a portion of the ethylene oxide, especially        10 to 50% by weight, especially 10 to 30% by weight, of the        total amount of ethylene oxide, an intermediate step comprising        a rest phase and/or a decompression and reaction with the        remaining portion of the ethylene oxide.

Preference is further given to a process as described above wherein stepa) comprises the following steps:

-   -   reaction of the monoethylenically unsaturated alcohol A1 with        the alkaline catalyst C1, reaction of the mixture of alcohol A1        and catalyst C1 with a portion of the ethylene oxide, especially        50 to 98% by weight, especially 80 to 98% by weight, of the        total amount of ethylene oxide,    -   a step for removal of low boilers, with decompression to a        pressure less than 100 mbar, preferably 50 to 100 mbar, and/or        elevated temperature, typically within the range from 30 to 150°        C.,    -   reaction of the resulting ethoxylation product with the alkaline        catalyst C1 and reaction of the remaining portion of the        ethylene oxide with the mixture of ethoxylation product and        alkaline catalyst C1.

Preference is further given to a process as described above wherein stepa) comprises the following steps:

-   -   reaction of the monoethylenically unsaturated alcohol A1 with        the alkaline catalyst C1, reaction of the mixture of alcohol A1        and catalyst C1 with a portion of the ethylene oxide, especially        50 to 98% by weight, especially 80 to 98% by weight, of the        total amount of ethylene oxide,    -   a step for removal of low boilers, with decompression to a        pressure less than 100 mbar, preferably 30 to 100 mbar, and/or        elevated temperature, typically within the range from 30 to 150°        C.,    -   reaction of the resulting ethoxylation product with the alkaline        catalyst C1 and reaction of the remaining portion of the        ethylene oxide with the mixture of ethoxylation product and        alkaline catalyst C1.

The alkaline catalyst C1 comprises especially 10 to 100% by weight KOMeand/or NaOMe, preferably 20 to 90% by weight. The catalyst C1 may, aswell as KOMe and/or NaOMe, comprise further alkaline compounds and/or asolvent (especially a C1 to C6 alcohol). For example, a compoundselected from alkali metal hydroxides, alkaline earth metal hydroxides,alkali metal alkoxides (C2 to C6 potassium alkoxides, C2 to C6 sodiumalkoxides, preferably ethoxide), alkaline earth metal alkoxides(especially C1 to C6 alkoxides, preferably methoxide and/or ethoxide)may be present. The catalyst C1 preferably comprises, as well as KOMeand/or NaOMe, at least one further alkaline compound selected fromsodium hydroxide and potassium hydroxide. In another preferredembodiment, the alkaline catalyst C1 consists of KOMe or of a mixture ofKOMe and methanol (MeOH). Typically, it is possible to use a solution of20 to 50% by weight of KOMe in methanol (MeOH).

In a further preferred embodiment, the alkaline catalyst C1 consists ofNaOMe or of a mixture of NaOMe and methanol (MeOH). Typically, asolution of 20 to 50% by weight NaOMe in methanol (MeOH) may be used.

In a further preferred embodiment, the alkaline catalyst C1 consists ofa mixture of KOMe and NaOMe or a solution of KOMe and NaOMe in methanol.

If the basic catalyst C1 used in the reaction in step a) is KOMe, it isadvantageous to use C1 in such an amount that an upper limit of 2500 ppm(approx. 0.4 mol %) of KOMe is maintained in relation to the alcohol A1used, in order to avoid the decomposition of the monoethylenicallyunsaturated alcohol A1. The concentration of potassium ions in step a)is preferably less than or equal to 0.4 mol % based on the total amountof the alcohol A1 used, more preferably 0.1 to 0.4 mol %.

If KOMe is added in such an amount that the concentration is more than0.9 mol % based on the ethoxylated alcohol A2 (product of process stepa)), KOMe has to be fully or partly removed prior to step b), in orderto obtain a potassium ion concentration of less than 0.9 mol % inprocess step b). This can be effected, for example, by isolating andoptionally purifying the ethoxylated alcohol A2 after step a).

In a further preferred embodiment, KOMe is used in such an amount thatthe concentration of potassium ions after the reaction in step a) isalready less than or equal to 0.9 mol % based on A2.

Step b) of the process according to the invention comprises the reactionof the ethoxylated alcohol A2 with at least one alkylene oxide Z, withaddition of an alkaline catalyst C2, to obtain an alkoxylated alcohol A3corresponding to the monomer (a) of formula (III)

H₂C═C(R¹)—R²—O—(—CH₂—CH₂—O—)_(k)—(—CH₂—CH(R³)—O—)_(l)—R⁴  (III)

where R⁴=H.

Step b) preferably first comprises the reaction of the ethoxylatedalcohol A2 with the alkaline catalyst C2. Typically, the alcohol A2, forthis purpose, is admixed in a pressure reactor with the alkalinecatalyst C2. Reduced pressure of typically less than 100 mbar,preferably in the range from 50 to 100 mbar and/or elevated temperaturetypically in the range from 30 to 150° C. allow water and/or low boilersstill present in the mixture to be drawn off. Thereafter, the alcohol ispresent essentially in the form of the corresponding alkoxide.Subsequently, the reaction mixture is typically treated with inert gas(e.g. nitrogen).

Step b) also preferably first comprises the reaction of the ethoxylatedalcohol A2 with the alkaline catalyst C2. Typically, the alcohol A2, forthis purpose, is admixed in a pressure reactor with the alkalinecatalyst C2. Reduced pressure of typically less than 100 mbar,preferably in the range from 30 to 100 mbar and/or elevated temperaturetypically in the range from 30 to 150° C. allow water and/or low boilersstill present in the mixture to be drawn off. Thereafter, the alcohol ispresent essentially in the form of the corresponding alkoxide.Subsequently, the reaction mixture is typically treated with inert gas(e.g. nitrogen).

Step b) preferably comprises the addition of the at least one alkyleneoxide Z to the above-described mixture of alcohol A2 with alkalinecatalyst C2. After the addition of the alkylene oxide Z has ended, thereaction mixture is typically allowed to react further. The additionand/or further reaction is effected typically over a period of 2 to 36h, preferably of 5 to 24 h, especially preferably of 5 to 20 h, morepreferably of 5 to 15 h.

Step b) preferably comprises the addition of the at least one alkyleneoxide Z to the above-described mixture of alcohol A2 with alkalinecatalyst C2. After the addition of the alkylene oxide Z has ended, thereaction mixture is typically allowed to react further. The additionincluding optional decompression an including further reaction iseffected typically over a period of 2 to 36 h, preferably of 5 to 30 h,especially preferably of 10 to 28 h, more preferably of 11 to 24 h.

According to the invention, the concentration of potassium ions in thereaction in step b) is less than or equal to 0.9 mol %, preferably lessthan 0.9 mol %, preferably from 0.01 to 0.9 mol %, more preferably from0.1 to 0.6 mol %, based on the alcohol A2 used. Preferably, theconcentration of potassium ions in the preparation of monomer (a), inthe reaction in step b), is 0.01 to 0.5 mol % based on the alcohol A2used.

In a particularly preferred embodiment, the concentration of potassiumions in the reaction in step b) is 0.1 to 0.5 mol % and the reaction instep b) is performed at temperatures of 120 to 130° C.

The alkaline catalyst C2 preferably comprises at least one alkalinecompound selected from alkali metal hydroxides, alkaline earth metalhydroxides, alkali metal alkoxides (especially C1 to C6 alkoxides,preferably methoxide and/or ethoxide), alkaline earth metal alkoxides(especially C1 to C6 alkoxides, preferably methoxide and/or ethoxide).The catalyst preferably comprises at least one basic sodium compound,especially selected from NaOH, NaOMe and NaOEt, more preferably NaOMe orNaOH. The catalyst C2 used may be a mixture of the alkaline compoundsmentioned; the catalyst C2 preferably consists of one of the basiccompounds mentioned or mixtures of the alkaline compounds mentioned.Frequently, an aqueous solution of the alkaline compounds is used. Inanother preferred embodiment, the alkaline catalyst C1 consists of NaOMeor of a mixture of NaOMe and methanol. Typically, a solution of 20 to50% by weight NaOMe in methanol may be used. The catalyst C2 preferablydoes not comprise any KOMe.

Preferably, the preparation in step b) involves using a catalyst C2comprising at least one basic sodium compound, especially selected fromNaOH, NaOMe and NaOEt, the concentration of sodium ions in the reactionin step b) being 3.5 to 12 mol %, preferably 3.5 to 7 mol %, morepreferably 4 to 5.5 mol %, based on the alcohol A2 used.

According to the invention, the reaction in step b) is performed at atemperature less than or equal to 135° C. Preference is given toperforming the reaction in step b) at temperatures of 60 to 135° C.,preferably at 100 to 135° C., more preferably at 120 to 130° C. Moreparticularly, step b) comprises the addition of the at least onealkylene oxide Z to a mixture of alcohol A2 with alkaline catalyst C2 ata temperature of less than or equal to 135° C., preferably attemperatures of 60 to 135° C., more preferably at 100 to 135° C., morepreferably at 120 to 135° C.

Preference is given to performing step b) at a pressure in the rangefrom 1 to 3.1 bar, preferably from 1 to 2.1 bar. In order to satisfy thesafety conditions, the reaction in step b) is preferably performed at apressure in the range of less than or equal to 3.1 bar (preferably 1 to3.1 bar) if R³ is a hydrocarbyl radical having 2 carbon atoms, orperformed at a pressure of less than or equal to 2.1 bar (preferably 1to 2.1 bar) if R³ is a hydrocarbyl radical having more than 2 carbonatoms.

Further preference is given to performing step b) at a pressure in therange from 1 to 6 bar, preferably from 1 to 3.1 bar, preferably from 1to 2.1 bar. The reaction in step b) is preferably performed at apressure in the range of from 1 to 6 bar, preferably from 1 to 3.1 bar,preferably from 4 to 6 bar, if R³ is a hydrocarbyl radical having 2carbon atoms. Especially, the addition of alkylene oxide Z and/or thefurther reaction are performed under the abovementioned pressures.

More particularly, the present invention relates to a copolymer where R³is a hydrocarbyl radical having 2 carbon atoms and step b) in thepreparation of monomer (a) is performed at a pressure in the range from1 to 3.1 bar; or where R³ is a hydrocarbyl radical having at least 3carbon atoms (preferably having 3 carbon atoms) and step b) in thepreparation of monomer (a) is performed at a pressure of 1 to 2.1 bar.

More particularly, the addition of alkylene oxide Z and/or the furtherreaction are performed at the abovementioned pressure. Step b)preferably comprises the addition of the at least one alkylene oxide Zto a mixture of alcohol A2 and alkaline catalyst K2 at a pressure in therange of less than or equal to 3.1 bar (preferably 1 to 3.1 bar) if R³is a hydrocarbyl radical having 2 carbon atoms, or at a pressure of lessthan or equal to 2.1 bar (preferably 1 to 2.1 bar) if R³ is ahydrocarbyl radical having at least 3 carbon atoms.

Step b) preferably comprises the addition of the at least one alkyleneoxide Z to a mixture of alcohol A2 with alkaline catalyst C2 over aperiod of less than or equal to 36 h, preferably less than or equal to32 h, more preferably over a period of 2 to 32 h, most preferably over aperiod of 5 to 24 h, and at a pressure of less than or equal to 3.1 bar,preferably at 1 to 2.1 bar (additionally preferably at theabovementioned pressures).

Step b) also preferably comprises the addition of the at least onealkylene oxide Z to a mixture of alcohol A2 with alkaline catalyst C2over a period of less than or equal to 36 h, preferably less than orequal to 32 h, more preferably over a period of 2 to 32 h, mostpreferably over a period of 11 to 24 h, and at a pressure of less thanor equal to 3.1 bar (additionally preferably at the abovementionedpressures).

Particular preference is given to performing step b) at a pressure inthe range from 1 to 3.1 bar (preferably at the abovementioned pressures)and at a temperature of 120 to 130° C.

The process according to the invention may optionally comprise step c),wherein at least a portion of the alkoxylated alcohol A3 is reacted withethylene oxide to obtain an alkoxylated alcohol A4 which corresponds tothe monomer (a) of the formula (I) where R⁴=H and m>0, preferably 0 to15, preferably 0 to 10, more preferably 0.1 to 10, more preferably 0.1to 5, especially preferably around 0.5 to 5 and most preferably around0.5 to 2.5. In a preferred embodiment, step c) comprises the reaction ofall of the alkoxylated alcohol A3 with ethylene oxide.

According to a preferred embodiment of the invention the processcomprises step c), wherein at least a portion of the alkoxylated alcoholA3 (preferably all of the alkoxylated alcohol A3) is reacted withethylene oxide to obtain an alkoxylated alcohol A4 which corresponds tothe macromonomer M of the formula (I) where R⁴=H and m is a number from0.1 to 15, preferably from 0.1 to 10, more preferably from 0.5 to 10,especially preferably from 1 to 7, further preferably from 2 to 5.

The optional step c) is especially effected without further addition ofan alkaline catalyst. The optional step c) is especially performed at apressure in the range from 1 to 7 bar, preferably from 1 to 5 bar, and atemperature in the range from 60 to 140° C., preferably from 120 to 140°C., more preferably from 125 to 135° C. The ethoxylation in the optionalstep c) is especially effected over a period of 0.5 to 7 h, especially0.5 to 5 h, preferably of 0.5 to 4 h.

The optional step c) is especially effected without further addition ofan alkaline catalyst. The optional step c) is especially performed at apressure in the range from 1 to 7 bar, preferably from 1 to 6 bar, and atemperature in the range from 60 to 140° C., preferably from 120 to1400° C., more preferably from 120 to 135° C. The ethoxylation in theoptional step c) is especially effected over a period of 0.5 to 7 h,especially 1 to 5 h, preferably of 1 to 4 h.

The optional step c) preferably comprises the addition of ethylene oxideto the reaction mixture after step b), comprising the alkoxylatedalcohol A3 of the formula (III) without further workup and/ordecompression. After the addition of the ethylene oxide has ended, thereaction mixture is typically allowed to react further. The additionand/or further reaction is effected typically over a period of 0.5 to 10h, especially 0.5 to 7 h, especially 0.5 to 5 h, preferably of 0.5 to 4h.

The optional step c) preferably comprises the addition of ethylene oxideto the reaction mixture after step b), comprising the alkoxylatedalcohol A3 of the formula (III) without further workup and/ordecompression. After the addition of the ethylene oxide has ended, thereaction mixture is typically allowed to react further. The additionincluding optional decompression and including further reaction iseffected typically over a period of 0.5 to 10 h, especially 2 to 10 h,especially 4 to 8 h.

The particular intended effect of performance of the optional step c),i.e. of a final ethoxylation, is that alkylene oxide Z possibly stillpresent in the reaction mixture after step b) is depleted and removed.

It is additionally possible to remove alkylene oxide Z which has notbeen depleted after step b) by a decompression and/or temperatureincrease after step b).

The process according to the invention may optionally comprise step d),wherein the alkoxylated alcohol A3 and/or A4 is etherified with acompound R⁴—X where X is a leaving group, preferably selected from Cl,Br, I, —O—SO₂—CH₃ (mesylate), —O—SO₂—CF₃ (triflate) and —O—SO₂—CR⁴.

If the alkoxylated alcohol A3 of the formula (III) and/or A4 of theformula (I) is to be etherified with a terminal OH group (i.e. R⁴=H),this can also be accomplished with the customary alkylating agents knownin principle to those skilled in the art, for example alkyl sulfatesand/or alkyl halides. The compound R⁴—X may typically comprise alkylhalides. For the etherification, it is also possible to use especiallydimethyl sulfate or diethyl sulfate. Etherification is just one optionwhich can be selected by the person skilled in the art according to thedesired properties of the copolymer.

Hydrophilic Monomers (b)

Over and above the monomers (a), the inventive hydrophobicallyassociating copolymer comprises at least one different monoethylenicallyunsaturated hydrophilic monomer (b). It will be appreciated that it isalso possible to use mixtures of a plurality of different hydrophilicmonomers (b).

The hydrophilic monomers (b) comprise, as well as an ethylenic group,one or more hydrophilic groups. These impart sufficient water solubilityto the inventive copolymer owing to their hydrophilicity. Thehydrophilic groups are especially functional groups comprising oxygenand/or nitrogen atoms. They may additionally comprise especially sulfurand/or phosphorus atoms as heteroatoms.

The monomers (b) are more preferably miscible with water in any ratio,but it is sufficient for execution of the invention that the inventivehydrophobically associating copolymer has the water solubility mentionedat the outset. In general, the solubility of the monomers (b) in waterat room temperature should be at least 100 g/l, preferably at least 200g/l and more preferably at least 500 g/l.

Examples of suitable functional groups comprise carbonyl groups >C═O,ether groups —O—, especially polyethyleneoxy groups —(CH₂—CH₂—O—)_(n)—where n is preferably a number from 1 to 200, hydroxyl groups —OH, estergroups —C(O)O—, primary, secondary or tertiary amino groups, ammoniumgroups, amide groups —C(O)—NH—, carboxamide groups —C(O)—NH₂ or acidicgroups such as carboxyl groups —COOH, sulfo groups —SO₃H, phosphonicacid groups —PO₃H₂ or phosphoric acid groups —OP(OH)₃.

Examples of preferred functional groups comprise hydroxyl groups —OH,carboxyl groups —COOH, sulfo groups —SO₃H, carboxamide groups —C(O)—NH₂,amide groups —C(O)—NH— and polyethyleneoxy groups —(CH₂—CH₂—O—)_(n)—Hwhere n is preferably a number from 1 to 200.

The functional groups may be attached directly to the ethylenic group,or else joined to the ethylenic group via one or more linkinghydrocarbyl groups.

The hydrophilic monomers (b) are preferably monomers of the generalformula H₂C═C(R⁵)R⁶ (IV) where R⁵ is H or methyl and R⁶ is a hydrophilicgroup or a group comprising one or more hydrophilic groups.

The R⁶ groups are groups which comprise heteroatoms in such an amountthat the water solubility defined at the outset is achieved.

Examples of suitable monomers (b) comprise monomers comprising acidicgroups, for example monomers comprising —COOH groups such as acrylicacid or methacrylic acid, crotonic acid, itaconic acid, maleic acid orfumaric acid, monomers comprising sulfo groups such as vinylsulfonicacid, allylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid(AMPS), 2-methacrylamido-2-methylpropanesulfonic acid,2-acrylamidobutanesulfonic acid, 3-acrylamido-3-methylbutanesulfonicacid or 2-acrylamido-2,4,4-trimethylpentanesulfonic acid, or monomerscomprising phosphonic acid groups such as vinylphosphonic acid,allylphosphonic acid, N-(meth)acrylamidoalkylphosphonic acids or(meth)acryloyloxyalkylphosphonic acids.

Mention should additionally be made of acrylamide and methacrylamide andderivatives thereof, for example N-methyl(meth)acrylamide,N,N′-dimethyl(meth)acrylamide and N-methylolacrylamide, N-vinylderivatives such as N-vinylformamide, N-vinylacetamide,N-vinylpyrrolidone or N-vinylcaprolactam, and vinyl esters such as vinylformate or vinyl acetate. N-Vinyl derivatives may, after polymerization,be hydrolyzed to vinylamine units, and vinyl esters to vinyl alcoholunits.

Further examples comprise monomers comprising hydroxyl and/or ethergroups, for example hydroxyethyl(meth)acrylate,hydroxypropyl(meth)acrylate, allyl alcohol, hydroxyvinyl ethyl ether,hydroxyvinyl propyl ether, hydroxyvinyl butyl ether or compounds of theformula H₂C═C(R¹)—O—(—CH₂—CH(R⁷)—O—)_(b)—R⁸ (V) where R¹ is as definedabove and b is a number from 2 to 200, preferably 2 to 100. The R⁷radicals are each independently H, methyl or ethyl, preferably H ormethyl, with the proviso that at least 50 mol % of the RB radicals areH. Preferably at least 75 mol % of the R⁷ radicals are H, morepreferably at least 90 mol %, and they are most preferably exclusivelyH. The R⁸ radical is H, methyl or ethyl, preferably H or methyl. Theindividual alkyleneoxy units may be arranged randomly or in blocks. Inthe case of a block copolymer, the transition between the blocks may beabrupt or gradual.

Further suitable hydrophilic monomers (b) are described in WO2011/133527 (page 15 lines 1-23).

The abovementioned hydrophilic monomers can of course be used not justin the acid or base form described, but also in the form ofcorresponding salts. It is also possible to convert acidic or basicgroups to corresponding salts after the formation of the polymer.Preferably, the corresponding salts are alkali metal salts or ammoniumsalts, more preferably organic ammonium salts and especially preferablywater-soluble organic ammonium salts.

Preference is given to a copolymer in which at least one of the monomers(b) is a monomer comprising acidic groups, the acidic groups being atleast one group selected from the group of —COOH, —SO₃H and —PO₃H, andsalts thereof.

At least one of the monomers (b) is preferably a monomer selected fromthe group of (meth)acrylic acid, vinylsulfonic acid, allylsulfonic acidand 2-acrylamido-2-methylpropanesulfonic acid (AMPS), more preferablyacrylic acid and/or APMS or salts thereof.

The invention preferably relates to a copolymer comprising at least twodifferent hydrophilic monomers (b) which are

-   -   at least one uncharged hydrophilic monomer (b1), and    -   at least one hydrophilic anionic monomer (b2) comprising at        least one acidic group selected from the group of —COOH, —SO₃H        and —PO₃H₂ and salts thereof.

Examples of suitable monomers (b1) comprise acrylamide andmethacrylamide, preferably acrylamide and derivatives thereof, forexample N-methyl(meth)acrylamide, N,N′-dimethyl(meth)acrylamide andN-methylolacrylamide. Mention should additionally be made of N-vinylderivatives such as N-vinylformamide, N-vinylacetamide,N-vinylpyrrolidone or N-vinylcaprolactam. Mention should additionally bemade of monomers having OH groups such as hydroxyethyl(meth)acrylate,hydroxypropyl(meth)acrylate, allyl alcohol, hydroxyvinyl ethyl ether,hydroxyvinyl propyl ether or hydroxyvinyl butyl ether. The monomer (b1)in the inventive copolymer is preferably acrylamide or derivativesthereof, more preferably acrylamide.

Examples of anionic monomers (b2) comprise acrylic acid or methacrylicacid, crotonic acid, itaconic acid, maleic acid or fumaric acid,monomers comprising sulfo groups such as vinylsulfonic acid,allylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (AMPS),2-methacrylamido-2-methylpropanesulfonic acid,2-acrylamidobutanesulfonic acid, 3-acrylamido-3-methylbutanesulfonicacid or 2-acrylamido-2,4,4-trimethylpentanesulfonic acid, or monomerscomprising phosphonic acid groups such as vinylphosphonic acid,allylphosphonic acid, N-(meth)acrylamidoalkylphosphonic acids or(meth)acryloyloxyalkylphosphonic acids.

Examples of preferred anionic monomers (b2) comprise acrylic acid,vinylsulfonic acid, allylsulfonic acid,2-acrylamido-2-methylpropanesulfonic acid (AMPS),2-acrylamidobutanesulfonic acid, 3-acrylamido-3-methylbutanesulfonicacid and 2-acrylamido-2,4,4-trimethylpentanesulfonic acid, veryparticular preference being given to2-acrylamido-2-methylpropanesulfonic acid (AMPS).

The copolymer is preferably one comprising acrylamide as monomer (b1)and a monomer comprising acidic groups as monomer (b2).

The copolymer is preferably one comprising acrylamide as monomer (b1)and a monomer comprising acidic groups as monomer (b2), the acidic groupbeing —SO₃H. The copolymer is especially preferably one comprisingacrylamide as monomer (b1) and 2-acrylamido-2-methylpropanesulfonic acid(AMPS) as monomer (b2).

The copolymer is preferably one comprising acrylamide as monomer (b1)and acrylic acid as monomer (b2).

The copolymer is additionally preferably one comprising acrylamide asmonomer (b1) and at least two further different monomers (b2) comprisingacidic groups. The copolymer is especially preferably one comprisingacrylamide as monomer (b1) and a monomer comprising the —SO₃H group anda monomer comprising the —COOH group as monomer (b2) comprising acidicgroups.

The copolymer is additionally preferably one comprising acrylamide asmonomer (b1), and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and amonomer comprising the —COOH group as monomer (b2). The copolymer isadditionally preferably one comprising acrylamide as monomer (b1), and2-acrylamido-2-methylpropanesulfonic acid (AMPS) and acrylic acid asmonomer (b2). The amount of the monomers (b) in the inventive copolymeris 25 to 99.9% by weight based on the total amount of all monomers inthe copolymer, preferably 25 to 99.5% by weight. The exact amount isguided by the nature and the desired end use of the hydrophobicallyassociating copolymers and is fixed accordingly by the person skilled inthe art.

The invention preferably relates to a copolymer comprising

-   -   (a) 2% by weight of at least one hydrophobically associating        monomer (a), and    -   (b) 50% by weight of acrylamide as an uncharged hydrophilic        monomer (b1), and    -   (c) 48% by weight of acrylamido-2-methylpropanesulfonic acid        (AMPS) as an anionic hydrophilic monomer (b2),        where the stated amounts are each based on the total amount of        all monomers in the copolymer.

Nonpolymerizable Surface-Active Components (c)

The inventive copolymers are prepared in the presence of at least onenonpolymerizable surface-active compound which is preferably at leastone nonionic surfactant. However, anionic and cationic surfactants arealso suitable, provided that they do not take part in the polymerizationreaction.

Component (c) is preferably at least one nonionic surfactant.

Component (c) may especially comprise surfactants, preferably nonionicsurfactants of the general formula R¹⁰—Y′ where R¹⁰ is a hydrocarbylradical having 8 to 32, preferably 10 to 20 and more preferably 12 to 18carbon atoms and Y′ is a hydrophilic group, preferably a nonionichydrophilic group, especially a polyalkoxy group.

The nonionic surfactant is preferably an ethoxylated long-chainaliphatic alcohol which has 10 to 20 carbon atoms and may optionallycomprise aromatic moieties.

Examples include: C₁₂C₁₄-fatty alcohol ethoxylates, C₁₆C₁₈-fatty alcoholethoxylates, C₁₃-oxo alcohol ethoxylates, C₁₀-oxo alcohol ethoxylates,C₁₃C₁₅-oxo alcohol ethoxylates, C₁₀-Guerbet alcohol ethoxylates andalkylphenol ethoxylates. Especially useful compounds have been found tobe those having 5 to 20 ethyleneoxy units, preferably 8 to 18ethyleneoxy units. It is optionally also possible for small amounts ofhigher alkyleneoxy units, especially propyleneoxy and/or butyleneoxyunits, to be present, in which case, however, the amount as ethyleneoxyunits should generally be at least 80 mol % based on all alkyleneoxyunits.

Especially suitable surfactants are those selected from the group of theethoxylated alkylphenols, the ethoxylated saturated iso-C13-alcoholsand/or the ethoxylated C10-Guerbet alcohols, with presence in each caseof 5 to 20 ethyleneoxy units, preferably 8 to 18 ethyleneoxy units, inthe alkoxy radicals.

Preparation of the Hydrophobically Associating Copolymers

The inventive copolymers can be prepared by methods known in principleto those skilled in the art, by free-radical polymerization of themonomers (a) and (b), for example by bulk, solution, gel, emulsion,dispersion or suspension polymerization, preferably in the aqueousphase, although each of the possible polymerization variants must beperformed in the presence of at least one component (c).

The present invention relates to a process for preparing anabove-described inventive copolymer wherein at least one hydrophobicallyassociating monomer (a) and at least one hydrophilic monomer (b) aresubjected to an aqueous solution polymerization in the presence of atleast one surface-active component (c), and wherein the monomer (a) ofthe general formula (I) is prepared by the above-described process.

In relation to the process for preparing the inventive copolymer, thepreferred embodiments which have been described above in connection withthe inventive copolymers apply.

The present invention preferably relates to a process for preparing theinventive copolymer, wherein the solution polymerization is performed ata pH of 5.0 to 7.5.

The monomers (a) of the formula (I) used in accordance with theinvention are provided by the preparation process detailed above, bymultistage alkoxylation of alcohols (II), optionally followed by anetherification. In relation to the process for preparing the monomer(a), the preferred embodiments which have been described above inconnection with the inventive copolymers apply.

In a preferred embodiment, the preparation of the copolymer isundertaken by means of gel polymerization in the aqueous phase, providedthat all monomers used have sufficient water solubility. For gelpolymerization, a mixture of the monomers, initiators and otherassistants with water or an aqueous solvent mixture is first provided.Suitable aqueous solvent mixtures comprise water and water-miscibleorganic solvents, the proportion of water generally being at least 50%by weight, preferably at least 80% by weight and more preferably atleast 90% by weight. Organic solvents which should be mentioned here areespecially water-miscible alcohols such as methanol, ethanol orpropanol. Acidic monomers can be fully or partly neutralized prior tothe polymerization. The concentration of all components except for thesolvents is typically 25 to 60% by weight, preferably 30 to 50% byweight.

The mixture is subsequently polymerized photochemically and/orthermally, preferably at −5° C. to 50° C. If polymerization is effectedthermally, preference is given to using polymerization initiators whichinitiate at comparatively low temperature, for example redox initiators.The thermal polymerization can be undertaken at room temperature or byheating the mixture, preferably to temperatures of not more than 50° C.The photochemical polymerization is typically undertaken at temperaturesfrom −5 to 10° C. It is particularly advantageously possible to combinephotochemical and thermal polymerization, by adding initiators both forthermal and for photochemical polymerization to the mixture. Thepolymerization here is first initiated photochemically at lowtemperatures, preferably −5 to +10° C. The heat of reaction releasedheats up the mixture and this additionally initiates the thermalpolymerization. By means of this combination, it is possible to achievea conversion of more than 99%.

Gel polymerization is generally effected without stirring. It can beeffected batchwise, by irradiating the mixture in a suitable vessel witha path length of 2 to 20 cm and/or heating it. The polymerization givesrise to a firm gel. The polymerization may also be continuous. For thispurpose, a polymerization apparatus having a conveyor belt toaccommodate the mixture to be polymerized is used. The conveyor belt isequipped with devices for heating or for irradiation with UV radiation.In this method, the mixture is poured by means of a suitable apparatusonto one end of the belt, the mixture is polymerized in the course oftransport in belt direction, and the firm gel can be removed at theother end of the belt.

After the polymerization, the gel is comminuted and dried. The dryingshould preferably be effected at temperatures below 100° C. To avoidconglutination, a suitable separating agent can be used for this step.The hydrophobically associating copolymer is obtained as a powder.

Further details regarding the performance of a gel polymerization aredisclosed, for example, in DE 10 2004 032 304 A1, paragraphs [0037] to[0041].

Inventive copolymers in the form of alkali-soluble aqueous dispersionscan preferably be prepared by means of emulsion polymerization. Theperformance of an emulsion polymerization using hydrophobicallyassociating monomers is disclosed, for example, in WO 2009/019225, page5 line 16 to page 8 line 13.

The inventive copolymers preferably have a number-average molecularweight Mn of 1 000 000 to 30 000 000 g/mol.

Use of the Hydrophobically Associating Copolymers

The inventive hydrophobically associating copolymers may, as alreadymentioned at the outset, be used in accordance with the invention tothicken aqueous phases.

The present invention relates to the use of the inventive copolymers inthe development, exploitation and completion of underground mineral oiland natural gas deposits. More particularly, the use relates to thepreferred embodiments which have been described above in connection withthe inventive copolymers.

The copolymers can be used alone here, or else in combination with otherthickening components, for example together with other thickeningpolymers. They can additionally be formulated, for example, togetherwith surfactants to give a thickening system. The surfactants can formmicelles in aqueous solution, and the hydrophobically associatingcopolymers together with the micelles can form a three-dimensionalthickening network.

For use, the copolymer can be dissolved directly in the aqueous phase tobe thickened. It is also conceivable to predissolve the copolymer andthen to add the solution formed to the system to be thickened.

Through the selection of the type and amount of the monomers (a) and(b), and of component (c), it is possible to adjust the properties ofthe copolymers to the respective technical demands.

The inventive copolymers can be used, for example, in the mineral oilproduction sector as an additive for thickening of drilling muds andcompletion fluids.

In addition, the inventive copolymers find use as a thickener inhydraulic fracturing. This typically involves injecting a high-viscosityaqueous solution under high pressure into the oil- or gas-bearingformation stratum.

The invention preferably relates to the use of the inventive copolymersfor tertiary mineral oil production, wherein an aqueous formulation ofsaid copolymers in a concentration of 0.01 to 5% by weight is injectedinto a mineral oil deposit through at least one injection well and crudeoil is withdrawn from the deposit through at least one production well.

The concentration of the copolymer should generally not exceed 5% byweight based on the sum of all constituents in the formulation and istypically 0.01 to 5% by weight, especially 0.1 to 5% by weight,preferably 0.5 to 3% by weight and more preferably 1 to 2% by weight.

The formulation is injected into the mineral oil deposit through atleast one injection well, and crude oil is withdrawn from the depositthrough at least one production well. The term “crude oil” in thiscontext of course means not only single-phase oil; instead, the termalso comprises the usual crude oil-water emulsions. In general, adeposit is provided with several injection wells and with severalproduction wells. The formulation injected, called the “polymer flood”,generates a pressure which causes the mineral oil to flow in thedirection of the production well and to be produced via the productionwell. The viscosity of the flooding medium should be matched as far aspossible to the viscosity of the mineral oil in the mineral oil deposit.The viscosity can especially be adjusted via the concentration of thecopolymer. Polymer flooding involves using an aqueous formulationcomprising not only water but also at least one hydrophobicallyassociating copolymer. It is of course also possible to use mixtures ofdifferent copolymers. In addition, further components may of course alsobe used. Examples of further components comprise biocides, stabilizersor inhibitors. The formulation can preferably be prepared by initiallycharging the water and sprinkling the copolymer in as a powder. Theaqueous formulation should be subjected to a minimum level of shearforces.

To increase the mineral oil yield, polymer flooding can advantageouslybe combined with other tertiary mineral oil production techniques.

The invention preferably relates to the use of the inventive copolymersin the development, exploitation and completion of underground mineraloil and natural gas deposits, especially for tertiary mineral oilproduction, the aqueous formulation of said copolymers comprising atleast one surfactant.

In a further preferred embodiment of the invention, the “polymerflooding” using the inventive hydrophobically associating copolymers canbe combined with a preceding “surfactant flooding”.

This involves, prior to the polymer flooding, first injecting an aqueoussurfactant formulation into the mineral oil formation. This reduces theinterfacial tension between the formation water and the actual mineraloil, and thus increases the mobility of the mineral oil in theformation. The combination of the two techniques allows an increase inthe mineral oil yield.

Examples of suitable surfactants for surfactant flooding comprisesurfactants having sulfate groups, sulfonate groups, polyoxyalkylenegroups, anionically modified polyoxyalkylene groups, betaine groups,glucoside groups or amine oxide groups, for examplealkylbenzenesulfonates, olefinsulfonates or amidopropyl betaines. It ispreferable to use anionic and/or betaine surfactants.

The person skilled in the art is aware of details of the industrialperformance of polymer flooding and of surfactant flooding, and employsan appropriate technique according to the type of deposit.

It will be appreciated that it is also possible to use surfactants andthe inventive copolymers in a mixture.

The following examples are intended to illustrate the invention indetail:

PART I: SYNTHESES I-a Preparation of the Monomers (a)

Unless mentioned explicitly, the reactions were conducted in such a waythat the target fill level at the end of the alkoxylation was about 65%of the reactor volume.

Example M1 HBVE-22 EO (0.4 Mol % of Potassium Ions)

A 2 l pressure autoclave with anchor stirrer was initially charged with135.3 g (1.16 mol) of hydroxybutyl vinyl ether (HBVE) (stabilized with100 ppm of potassium hydroxide (KOH)) and the stirrer was switched on.1.06 g of potassium methoxide (KOMe) solution (32% KOMe in methanol(MeOH), corresponding to 0.0048 mol of potassium) were fed in and thestirred vessel was evacuated to a pressure less than 10 mbar, heated to80° C. and operated at 80° C. and a pressure of less than 10 mbar for 70min. MeOH was distilled off.

According to an alternative procedure the potassium methoxide (KOMe)solution (32% KOMe in methanol (MeOH)) were fed in and the stirredvessel was evacuated to a pressure of 10-20 mbar, heated to 65° C. andoperated at 65° C. and a pressure of 10-20 mbar for 70 min. MeOH wasdistilled off.

The mixture was purged three times with N₂ (nitrogen). Thereafter, thevessel was checked for pressure retention, 0.5 bar gauge (1.5 barabsolute) was set and the mixture was heated to 120° C. The mixture wasdecompressed to 1 bar absolute and 1126 g (25.6 mol) of ethylene oxide(EO) were metered in until p_(max) was 3.9 bar absolute and T_(max) was150° C. After 300 g of EO had been added, the metered addition wasstopped (about 3 h after commencement) for a wait period of 30 min andthe mixture was decompressed to 1.3 bar absolute. Thereafter, the restof the EO was metered in. The metered addition of EO including thedecompression took a total of 10 h.

Stirring was continued up to constant pressure at approx. 145-150° C. (1h), and the mixture was cooled to 100° C. and freed of low boilers at apressure of less than 10 mbar for 1 h. The material was transferred at80° C. under N₂.

The analysis (OH number, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD) confirmedthe structure.

Example M2 HBVE-22 EO-10.6 PeQ (0.4 Mol % of Potassium Ions, 4.6 Mol %of Sodium Ions), Addition of the PeQ at 140° C. to 3.2 Bar

A 2 l pressure autoclave with anchor stirrer was initially charged with135.3 g (1.16 mol) of HBVE (stabilized with 100 ppm of KOH) and thestirrer was switched on. 1.06 g of KOMe solution (32% KOMe in MeOH,corresponding to 0.0048 mol of K) were fed in and the stirred vessel wasevacuated to <10 mbar, heated to 80° C. and operated at 80° C. and <10mbar for 70 min. MeOH was distilled off.

According to an alternative procedure the potassium methoxide (KOMe)solution (32% KOMe in methanol (MeOH)) were fed in and the stirredvessel was evacuated to a pressure of 10-20 mbar, heated to 65° C. andoperated at 65° C. and a pressure of 10-20 mbar for 70 min. MeOH wasdistilled off.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) was setand the mixture was heated to 120° C. The mixture was decompressed to 1bar absolute and 255 g (5.8 mol) of EO were metered in until p_(max) was3.9 bar absolute and T_(max) was 150° C. Stirring was continued up toconstant pressure at approx. 145-150° C. (1 h), and the mixture wascooled to 100° C. and freed of low boilers at a pressure of less than 10mbar for 1 h. The material (HBVE-5 EO) was transferred at 80° C. underN₂.

A 2 l pressure autoclave with anchor stirrer was initially charged with180 g (0.54 mol) of the above HBVE-5 EO and the stirrer was switched on.Thereafter, 4.32 g of 30% NaOMe (sodium methoxide) in MeOH solution(0.024 mol of NaOMe, 1.30 g of NaOMe) were added, a reduced pressure of<10 mbar was applied, and the mixture was heated to 100° C. and keptthere for 80 min, in order to distill off the MeOH. The mixture waspurged three times with N₂. Thereafter, the vessel was checked forpressure retention, 0.5 bar gauge (1.5 bar absolute) was set and themixture was heated to 150° C. The mixture was decompressed to 1.0 barabsolute. 398 g (9.04 mol) of EO were metered in up to a pressure of 2bar absolute and the reaction was allowed to continue for 1 h. Themixture was cooled to 140° C. and 502 g (5.83 mol) of PeO (pentyleneoxide) were metered in at 1.2 bar absolute and 140° C. until thepressure rose to 3.2 bar absolute. The PeO was metered in within twohours. The mixture was cooled to 80° C., and residual oxide was drawnoff until the pressure was below 10 mbar for at least 10 min. The vacuumwas broken with N₂ and 100 ppm of BHT (butylhydroxytoluene) were added.The transfer was effected at 80° C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M3 HBVE-22 EO-10.5 PeO (0.4 Mol % of Potassium Ions, 3.3 Mol %of Sodium Ions), Addition of the PeO at 140° C. to 2.1 Bar

A 2 l pressure autoclave with anchor stirrer was initially charged with135.3 g (1.16 mol) of hydroxybutyl vinyl ether (stabilized with 100 ppmof KOH) and the stirrer was switched on. 1.06 g of KOMe solution (32%KOMe in MeOH, corresponding to 0.0048 mol of K) were fed in and thestirred vessel was evacuated to <10 mbar, heated to 80° C. and operatedat 800° C. and <10 mbar for 70 min. MeOH was distilled off.

According to an alternative procedure the potassium methoxide (KOMe)solution (32% KOMe in methanol (MeOH)) were fed in and the stirredvessel was evacuated to a pressure of 10-20 mbar, heated to 65° C. andoperated at 65° C. and a pressure of 10-20 mbar for 70 min. MeOH wasdistilled off.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) was setand the mixture was heated to 120° C. The mixture was decompressed to 1bar absolute and 255 g (5.8 mol) of EO were metered in until p_(max) was3.9 bar absolute and T_(max) was 150° C. The mixture was freed of lowboilers down to constant pressure as 10 mbar for 1 h. The material(HBVE-5 EO) was transferred at 80° C. under N₂.

A 2 l pressure autoclave with anchor stirrer was initially charged with180 g (0.54 mol) of HBVE-5 EO and the stirrer was switched on.Thereafter, 3.18 g of 30% NaOMe in MeOH solution (0.018 mol of NaOMe,0.95 g of NaOMe) were added, a reduced pressure of <10 mbar was applied,and the mixture was heated to 100° C. and kept there for 80 min, inorder to distill off the MeOH. The mixture was purged three times withN₂. Thereafter, the vessel was checked for pressure retention, 0.5 bargauge (1.5 bar absolute) was set and the mixture was heated to 150° C.The mixture was decompressed to 1.0 bar absolute. 398 g (9.04 mol) of EOwere metered in up to a pressure of 2 bar absolute, reaction was allowedto continue for 1 h, then the mixture was cooled to 100° C. and freed oflow boilers at a pressure of less than 10 mbar for 1 h. The material(HBVE-22 EO) was transferred at 80° C. under N₂.

A 1 l autoclave with anchor stirrer was initially charged with 450 g(0.425 mol) of the above HBVE-22 EO and the stirrer was switched on. Themixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) was setand the mixture was heated to 140° C. The mixture was decompressed to1.0 bar absolute.

Then, at 1.4 bar absolute and 140° C., 384 g (5.83 mol) of PeO weremetered in at 48 g/h until the pressure rose to 2.1 bar absolute. Twointerruptions were necessary. The mixture was left to react at 140° C.until the pressure fell again. The PeO was metered in within two days.The mixture was cooled to 80° C. and residual oxide was drawn off untilthe pressure was below 10 mbar for at least 10 min. The vacuum wasbroken with N₂ and 100 ppm of BHT were added. The transfer was effectedat 80° C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M4 HBVE-22 EO-10 PeO (0.4 Mol % of Potassium Ions, 4.6 Mol % ofSodium Ions), Addition of the PeO at 127° C. to 2.1 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 745 g(0.69 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,5.36 g of 32% NaOMe in MeOH solution (0.0317 mol of NaOMe, 1.71 g ofNaOMe) were added, a reduced pressure of <10 mbar was applied, and themixture was heated to 80° C. and kept there for 80 min, in order todistill off the MeOH.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 127° C. and then the pressure was set to1 bar absolute.

591 g (6.9 mol) of PeO were metered in at 127° C.; p_(max) was 2.1 barabsolute. Two intermediate decompressions were necessary owing toincreasing fill level. The PeO metering was stopped, and the mixture wasleft to react for 2 h until the pressure was constant and decompressedto 1.0 bar absolute. Thereafter, the metered addition of PeO wascontinued. P_(max) was still 2.1 bar. After metered addition of PeO hadended, reaction was allowed to continue to constant pressure or for 4 h.The mixture was cooled to 110° C. and residual oxide was drawn off untilthe pressure was below mbar for at least 10 min. Then 0.5% water wasadded at 110° C. and volatiles were subsequently drawn off until thepressure was below 10 mbar for at least 10 min. The vacuum was brokenwith N₂ and 100 ppm of BHT were added. The transfer was effected at 800°C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M5 HBVE-22 EO-11 PeO (0.4 Mol % of Potassium Ions, 4.6 Mol % ofSodium Ions), Addition of the PeO at 127° C. to 2.1 Bar

The preparation was analogous to example M4, except that 11 rather than10 eq (molar equivalents) of PeO were added.

Example M6 HBVE-24.5 EO-11 PeO (0.4 Mol % of Potassium Ions, 4.6 Mol %of Sodium Ions), Addition of the PeO at 127° C. to 2.1 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 650 g(0.60 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,5.96 g of 25% NaOMe in MeOH solution (0.0276 mol of NaOMe, 1.49 g ofNaOMe) were added, a reduced pressure of <10 mbar was applied, and themixture was heated to 100° C. and kept there for 80 min, in order todistill off the MeOH.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 120° C. and then the pressure was set to1 bar absolute. 66 g (1.577 mol) of EO were metered in at 127° C.;p_(max) was 2.1 bar absolute. After waiting for 30 min for establishmentof constant pressure, the mixture was decompressed to 1.0 bar absolute.567 g (6.6 mol) of PeO were metered in at 127° C.; p_(max) was 2.1 barabsolute. Two intermediate decompressions were necessary owing toincreasing fill level. The PeO metering was stopped, and the mixture wasleft to react for 2 h until the pressure was constant and decompressedto 1.0 bar absolute. Thereafter, the metered addition of PeO wascontinued. P_(max) was still 2.1 bar. After metered addition of PeO hadended, reaction was allowed to continue to constant pressure or for 4 h.The mixture was cooled to 110° C. and residual oxide was drawn off untilthe pressure was below 10 mbar for at least 10 min. Then 0.5% water wasadded at 110° C. and volatiles were subsequently drawn off until thepressure was below 10 mbar for at least 10 min. The vacuum was brokenwith N₂ and 100 ppm of BHT were added. The transfer was effected at 80°C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M7 HBVE-24.5 EO-10 PeO (0.4 Mol % of Potassium Ions, 4.6 Mol %of Sodium Ions), Addition of the PeO at 127° C. to 2.1 Bar

Preparation was analogous to example M6, except that 10 rather than 11eq of pentene oxide were added.

Example M8 HBVE-24.5 EO-10 PeO (0.9 Mol % of Potassium Ions, 4.1 Mol %of Sodium Ions), Addition of the PeO at 127° C. to 2.1 Bar

The preparation was analogous to example M6, except that the catalystconcentration was 0.9 mol % of potassium ions and 4.1 mol % of sodiumions and 10 rather than 11 eq of PeO were added.

Example M9 HBVE-24.5 EO-10 PeO (1.5 Mol % of Potassium Ions, 4.6 Mol %of Sodium Ions), Addition of the PeO at 127° C. to 2.1 Bar

The preparation was analogous to example M6, except that the catalystconcentration was 1.5 mol % of potassium ions and 4.1 mol % of sodiumions and 10 rather than 11 eq of PeO were added.

Example M10 HBVE-24.5 EO-10 PeO (0.4 Mol % of Potassium Ions, 5.5 Mol %of Sodium Ions), Addition of the PeO at 127° C. to 2.1 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 684.0g (0.631 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,2.78 g of 50% NaOH (sodium hydroxide) solution (0.0348 mol of NaOH, 1.39g of NaOH) were added, a reduced pressure of <10 mbar was applied, andthe mixture was heated to 100° C. and kept there for 80 min, in order todistill off the water.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 120° C. and then the pressure was set to1.6 bar absolute. 69.4 g (1.577 mol) of EO were metered in at 127° C.;p_(max) was 2.1 bar absolute. After waiting for 30 min for establishmentof constant pressure, the mixture was decompressed to 1.0 bar absolute.

542.5 g (6.03 mol) of PeO were metered in at 127° C.; p_(max) was 2.1bar absolute. One intermediate decompression was necessary owing toincreasing fill level. The PeO metering was stopped, and the mixture wasleft to react for 1 h until the pressure was constant and decompressedto 1.0 bar absolute. Thereafter, the metered addition of PeO wascontinued. P_(max) was still 2.1 bar (first decompression after 399 g ofPeO, total PeO metering time 7 h incl. decompression break). Aftermetered addition of PeO had ended, reaction was allowed to continue toconstant pressure or for 3 h. The mixture was cooled to 110° C., andresidual oxide was removed under reduced pressure until the pressure wasbelow 10 mbar for at least 10 min. Then 0.5% water was added at 110° C.and volatiles were subsequently drawn off until the pressure was below10 mbar for at least 10 min. The vacuum was broken with N₂ and 100 ppmof BHT were added. The transfer was effected at 80° C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M11 HBVE-24.5 EO-9 PeO (0.4 Mol % of Potassium Ions, 5.5 Mol %of Sodium Ions), Addition of the PeO at 127° C. to 2.1 Bar

The preparation was analogous to example M10, except that 9 rather than10 eq of PeO were added.

Example M12 HBVE-24.5 EO-9 PeO (5.8 mol % of potassium ions), additionof the PeO at 127° C. to 2.1 bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 889.2g (0.820 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,9.69 g of 32% KOMe in MeOH solution (0.0443 mol of KOMe, 3.11 g KOMe)were added, a reduced pressure of <10 mbar was applied, and the mixturewas heated to 80° C. and kept there for 80 min, in order to distill offMeOH.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 120° C. and then the pressure was set to1 bar absolute. 90.2 g (2.050 mol) of EO were metered in up to 140° C.After waiting for 30 min for establishment of constant pressure, themixture was decompressed to 1.0 bar absolute at 120° C.

A relatively large sample was taken, such that 789 g (0.66 mol) ofHBVE-24.5 EO remained in the reactor. For safety, the mixture wasinertized again with N₂, set to 1.0 bar absolute and heated to 127° C.511 g (5.95 mol) of PeO were metered in at 127° C.; p_(max) was 2.1 barabsolute. One intermediate decompression was necessary owing toincreasing fill level. The PeO metering was stopped, and the mixture wasleft to react for 2 h until pressure was constant and decompressed to1.0 bar absolute. Thereafter, the metered addition of PeO was continued.P_(max) was still 2.1 bar. After metered addition of PeO had ended,reaction was allowed to continue to constant pressure or for 3 h. Themixture was cooled to 110° C., and residual oxide was removed underreduced pressure until the pressure was below 10 mbar for at least 10min. Then 0.5% water was added at 110° C. and volatiles weresubsequently drawn off until the pressure was below 10 mbar for at least10 min. The vacuum was broken with N₂ and 100 ppm of BHT were added. Thetransfer was effected at 80° C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1 H NMR in MeOD)confirmed the structure.

Example M13 HBVE-24.5 EO-8 PeO (0.4 Mol % of Potassium Ions, 4.6 Mol %of Sodium Ions), Addition of the PeO at 127° C. to 2.1 Bar

The preparation was analogous to example M6, except that 8 rather than11 eq of PeO were added.

Example M14 HBVE-26.5 EO-10 PeO (0.4 Mol % of Potassium Ions, 5.5 Mol %of Sodium Ions), Addition of the PeO at 1270° C. to 2.1 Bar

The preparation was analogous to example M10, except that, proceedingfrom HBVE-22 EO, 4.5 eq of EO rather than 2.5 eq of EO were added.

Example M15 HBVE-24.5 EO-10 PeO (0.4 Mol % of Potassium Ions, 5.5 Mol %of Sodium Ions), Addition of the PeO at 122° C. to 2.1 Bar

The preparation was analogous to example M10, except that PeO was addedat 122° C. rather than 127° C.

Example M16 HBVE-24.5 EO-10 PeO (0.4 Mol % of Potassium Ions, 5.5 Mol %of Sodium Ions), Addition of the PeO at 132° C. to 2.1 Bar

The preparation was analogous to example M10, except that PeO was addedat 132° C. rather than 127° C.

Example M17 HBVE-24.5 EO-10 BuO (0.4 Mol % of Potassium Ions, 5.5 Mol %of Sodium Ions), Addition of the BuO at 127° C. to 2.1 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 730.8g (0.674 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,2.97 g of 50% NaOH solution (0.0371 mol of NaOH, 0.85 g of NaOH) wereadded, a reduced pressure of <10 mbar was applied, and the mixture washeated to 100° C. and kept there for 80 min, in order to distill off thewater.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 120° C. and then the pressure was set to1.6 bar absolute. 74.1 g (1.685 mol) of EQ were metered in up to 127°C.; p_(max) was 3.9 bar absolute. After waiting for 30 min forestablishment of constant pressure, the mixture was decompressed to 1.0bar absolute.

485.3 g (6.74 mol) of BuO (butylene oxide) were metered in at 127° C.;p_(max) was 2.1 bar absolute. One intermediate decompression wasnecessary owing to increasing fill level. The BuO metering was stopped,and the mixture was left to react for 1 h until pressure was constantand decompressed to 1.0 bar absolute. Thereafter, the metered additionof BuQ was continued. P_(max) was still 2.1 bar (first decompressionafter 246 g of BuO, total BuO metering time 10 h incl. decompressionbreak). After metered addition of BuO had ended, reaction was allowed tocontinue to constant pressure or for 3 h. The mixture was cooled to 110°C., and residual oxide was drawn off until the pressure was below 10mbar for at least 10 min. Then 0.5% water was added at 110° C. andvolatiles were subsequently drawn off until the pressure was below 10mbar for at least 10 min. The vacuum was broken with N₂ and 100 ppm ofBHT were added. The transfer was effected at 80° C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure,

Example M18 HBVE-24.5 EO-12 BuO (0.4 Mol % of Potassium Ions, 5.5 Mol %of Sodium Ions), Addition of the BuO at 127° C. to 2.1 Bar

The preparation was analogous to example M17, except that 12 rather than10 eq of BuO were added.

Example M19 HBVE-24.5 EO-14 BuO (0.4 Mol % of Potassium Ions, 5.5 Mol %of Sodium Ions), Addition of the BuO at 127° C. to 2.1 Bar

The preparation was analogous to example M17, except that 14 rather than10 eq of BuO were added.

Example M20 HBVE-24.5 EO-16 BuO (0.4 Mol % of Potassium Ions, 5.5 Mol %of Sodium Ions), Addition of the BuO at 127° C. to 2.1 Bar

The preparation was analogous to example M17, except that 16 rather than10 eq of BuO were added.

Example M21 HBVE-24.5 EO-18 BuO (0.4 Mol % of Potassium Ions, 5.5 Mol %of Sodium Ions), Addition of the BuO at 127° C. to 2.1 Bar

The preparation was analogous to example M17, except that 18 rather than10 eq of BuO were added.

Example M22 HBVE-24.5 EO-16 BuO (5.8 Mol % of Potassium Ions), Additionof the BuO at 127° C. to 3.1 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 622.8g (0.575 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,6.92 g of 32% KOMe in MeOH solution (0.0316 mol of KOMe, 2.21 g of KOMe)were added, a reduced pressure of <10 mbar was applied, and the mixturewas heated to 80° C. and kept there for 80 min, in order to distill offthe methanol.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 120° C. and then the pressure was set to1.6 bar absolute. 50.3 g (1.144 mol) of EO were metered in up to 127°C.; P_(max) was 3.9 bar absolute. After waiting for 30 min forestablishment of constant pressure, the mixture was decompressed to 1.0bar absolute.

662 g (9.19 mol) of BuO were metered in at 127° C.; p_(max) was 3.1 barabsolute. After metered addition of BuO had ended, reaction was allowedto continue to constant pressure or for 5 h. The mixture was cooled to110° C., and residual oxide was drawn off until the pressure was below10 mbar for at least 10 min. Then 0.5% water was added at 110° C. andvolatiles were subsequently drawn off until the pressure was below 10mbar for at least 10 min. The vacuum was broken with N₂ and 100 ppm ofBHT were added. The transfer was effected at 80° C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M23 HBVE-24.5 EO-16 BuO (0.4 Mol % of Potassium Ions, 11 Mol %of Sodium Ions), Addition of the BuO at 127° C. to 3.1 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 595.1g (0.549 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,4.83 g of 50% NaOH solution (0.060 mol of NaOH, 2.41 g of NaOH) wereadded, a reduced pressure of <10 mbar was applied, and the mixture washeated to 100° C. and kept there for 80 min, in order to distill off thewater.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 120° C. and then the pressure was set to1.6 bar absolute. 60.4 g (1.373 mol) of EO were metered in up to 127°C.; p_(max) was 3.9 bar absolute. After waiting for 30 min forestablishment of constant pressure, the mixture was decompressed to 1.0bar absolute.

632.2 g (8.748 mol) of BuO were metered in at 127° C.; p_(max) was 3.1bar absolute. One intermediate decompression was necessary owing toincreasing fill level. The BuO metering was stopped, and the mixture wasleft to react for 1 h until pressure was constant and decompressed to1.0 bar absolute. Thereafter, the metered addition of BuO was continued.P_(max) was still 3.1 bar (first decompression after 334 g of BuO, totalBuO metering time 5 h incl. decompression break). After metered additionof BuO had ended, the mixture was heated to 135° C. and reaction wasallowed to continue for 3.5 h. The mixture was cooled to 100° C., andresidual oxide was drawn off until the pressure was below 10 mbar for atleast 10 min. Then 0.5% water was added at 120° C. and volatiles weresubsequently drawn off until the pressure was below 10 mbar for at least10 min. The vacuum was broken with N₂ and 100 ppm of BHT were added. Thetransfer was effected at 80° C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M24 HBVE-23 EO-17 BuO-2.5 EO (0.4 Mol % of Potassium Ions, 5.5Mol % of Sodium Ions), Addition of the BuO at 127° C. to 3.1 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 576.7g (0.532 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,2.33 g of 50% NaOH solution (0.029 mol of NaOH, 1.17 g of NaOH) wereadded, a reduced pressure of <10 mbar was applied, and the mixture washeated to 100° C. and kept there for 80 min, in order to distill off thewater.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 127° C. and then the pressure was set to1.6 bar absolute. 23.4 g (0.532 mol) of EO were metered in at 127° C.;p_(max) was 3.9 bar absolute. After waiting for 30 min for establishmentof constant pressure, the mixture was decompressed to 1.0 bar absolute.

651.2 g (9.044 mol) of BuO were metered in at 127° C.; p_(max) was 3.1bar absolute. After metered addition of BuO had ended, the mixture washeated to 135° C. and reaction was allowed to continue for 2 h.Thereafter 58.5 g (1.331 mol) of EO were metered at 135° C.; p_(max) was3.2 bar absolute. After metered addition of EO had ended, the reactionwas allowed to continue for 2 h.

The mixture was cooled to 100° C., and residual oxide was drawn offuntil the pressure was below mbar for at least 10 min. Then 0.5% waterwas added at 120° C. and volatiles were subsequently drawn off until thepressure was below 10 mbar for at least 10 min. The vacuum was brokenwith N₂ and 100 ppm of BHT were added. The transfer was effected at 80°C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M25 HBVE-24.5 EQ-16 BuO-3.5 EO (0.4 Mol % of Potassium Ions, 5.5Mol % of Sodium Ions), Addition of the BuO at 127° C. to 3.1 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 588.6g (0.543 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,2.39 g of 50% NaOH solution (0.030 mol of NaOH, 1.19 g of NaOH) wereadded, a reduced pressure of <10 mbar was applied, and the mixture washeated to 100° C. and kept there for 80 min, in order to distill off thewater.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 127° C. and then the pressure was set to1.6 bar absolute. 59.7 g (1.358 mol) of EQ were metered in at 127° C.;p_(max) was 3.9 bar absolute. After waiting for 30 min for establishmentof constant pressure, the mixture was decompressed to 1.0 bar absolute.

625.5 g (8.688 mol) of BuO were metered in at 127° C.; p_(max) was 3.1bar absolute. One intermediate decompression was necessary owing toincreasing fill level. The BuO metering was stopped, and the mixture wasleft to react for 1 h until pressure was constant and decompressed to1.0 bar absolute. Thereafter, the metered addition of BuO was continued.P_(max) was still 3.1 bar (first decompression after 610 g of BuO, totalBuO metering time 8 h incl. decompression break). After metered additionof BuO had ended, the reaction was allowed to continue for 8 h andthereafter the mixture was heated to 135° C. Thereafter 83.6 g (1.901mol) of EO were metered at 135° C.; p_(max) was 3.1 bar absolute. Aftermetered addition of EO had ended, the reaction was allowed to continuefor 4 h. The mixture was cooled to 100° C., and residual oxide was drawnoff until the pressure was below 10 mbar for at least 10 min. Then 0.5%water was added at 120° C. and volatiles were subsequently drawn offuntil the pressure was below 10 mbar for at least 10 min. The vacuum wasbroken with N₂ and 100 ppm of BHT were added. The transfer was effectedat 80° C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M26 HBVE-24.5 EO-16 BuO-5 EO (0.4 Mol % of Potassium Ions, 5.5Mol % of Sodium Ions), Addition of the BuO at 127° C. to 3.1 Bar

The starting material used was monomer M1 from example M1. Thepreparation was analogous to example M25, except that 5 rather than 3.5eq of EO were added after addition of BuO and polymerisation, i.e. 119.5g (2.715 mol) of EO were metered at 135° C.

The analysis (mass spectrum, GPC, 1H NMR in CDCl3, 1H NMR in MeOD)confirmed the structure.

Example M27 HBVE-24.5 EO-10 BuO-3.5 EO (0.4 Mol % of Potassium Ions, 5.5Mol % of Sodium Ions), Addition of the BuO at 127° C. to 3.1 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 685.2g (0.632 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,2.78 g of 50% NaOH solution (0.035 mol of NaOH, 1.39 g of NaOH) wereadded, a reduced pressure of <10 mbar was applied, and the mixture washeated to 100° C. and kept there for 80 min, in order to distill off thewater.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 127° C. and then the pressure was set to1.6 bar absolute. 69.8 g (1.587 mol) of EQ were metered in at 127° C.;p_(max) was 3.9 bar absolute. After waiting for 30 min for establishmentof constant pressure, the mixture was decompressed to 1.0 bar absolute.

455.2 g (6.322 mol) of BuO were metered in at 127° C.; p_(max) was 3.1bar absolute. After metered addition of BuO had ended, the reaction wasallowed to continue for 7 h. Thereafter 97.4 g (2.213 mol) of EO weremetered at 127° C.; p_(max) was 3.1 bar absolute. After metered additionof EO had ended, the reaction was allowed to continue for 2 h. Themixture was cooled to 100° C., and residual oxide was drawn off untilthe pressure was below 10 mbar for at least 10 min. Then 0.5% water wasadded at 120° C. and volatiles were subsequently drawn off until thepressure was below 10 mbar for at least 10 min. The vacuum was brokenwith N₂ and 100 ppm of BHT were added. The transfer was effected at 80°C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M28 HBVE-24.5 EO-5 BuO-3.5 EO (0.4 Mol % of Potassium Ions, 5.5Mol % of Sodium Ions), Addition of the BuO at 127° C. to 3.1 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 822.0g (0.758 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,3.34 g of 50% NaOH solution (0.042 mol of NaOH, 1.67 g of NaOH) wereadded, a reduced pressure of <10 mbar was applied, and the mixture washeated to 100° C. and kept there for 80 min, in order to distill off thewater.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 127° C. and then the pressure was set to1.6 bar absolute. 83.4 g (1.895 mol) of EO were metered in at 127° C.;p_(max) was 3.9 bar absolute. After waiting for 30 min for establishmentof constant pressure, the mixture was decompressed to 1.0 bar absolute.

273.0 g (3.792 mol) of BuO were metered in at 127° C.; p_(max) was 3.1bar absolute. After metered addition of BuO had ended, the reaction wasallowed to continue for 15 h. Thereafter 116.8 g (2.654 mol) of EO weremetered at 127° C.; P_(max) was 3.1 bar absolute. After metered additionof EO had ended, the reaction was allowed to continue for 4 h. Themixture was cooled to 100° C., and residual oxide was drawn off untilthe pressure was below 10 mbar for at least 10 min. Then 0.5% water wasadded at 120° C. and volatiles were subsequently drawn off until thepressure was below 10 mbar for at least 10 min. The vacuum was brokenwith N₂ and 100 ppm of BHT were added. The transfer was effected at 80°C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M29 HBVE-24.5 EO-22 BuO-3.5 EO (0.4 Mol % of Potassium Ions, 5.5Mol % of Sodium Ions), Addition of the BuO at 127° C. to 3.1 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 493.3g (0.455 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,2.00 g of 50% NaOH solution (0.025 mol of NaOH, 1.00 g of NaOH) wereadded, a reduced pressure of <10 mbar was applied, and the mixture washeated to 100° C. and kept there for 80 min, in order to distill off thewater.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 127° C. and then the pressure was set to1.6 bar absolute. 50.0 g (1.138 mol) of EO were metered in at 127° C.;p_(max) was 3.9 bar absolute. After waiting for 30 min for establishmentof constant pressure, the mixture was decompressed to 1.0 bar absolute.

720.9 g (10.012 mol) of BuO were metered in at 127° C.; p_(max) was 3.1bar absolute. After metered addition of BuO had ended, the reaction wasallowed to continue for 9 h. The mixture was heated to 135° C.Thereafter 70.1 g (1.593 mol) of EO were metered at 135° C.; p_(max) was3.1 bar absolute. After metered addition of EO had ended, the reactionwas allowed to continue for 2 h. The mixture was cooled to 100° C., andresidual oxide was drawn off until the pressure was below 10 mbar for atleast 10 min. Then 0.5% water was added at 120° C. and volatiles weresubsequently drawn off until the pressure was below 10 mbar for at least10 min. The vacuum was broken with N₂ and 100 ppm of BHT were added. Thetransfer was effected at 80° C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

Example M30 HBVE-24.5 EO-16 BuO-3.5 EO (0.4 Mol % of Potassium Ions, 5.5Mol % of Sodium Ions), Addition of the BuO at 127° C. at from 4 to 6 Bar

The starting material used was monomer M1 from example M1. A 2 lpressure autoclave with anchor stirrer was initially charged with 568.6g (0.525 mol) of HBVE-22 EO and the stirrer was switched on. Thereafter,2.31 g of 50% NaOH solution (0.029 mol of NaOH, 1.16 g of NaOH) wereadded, a reduced pressure of <10 mbar was applied, and the mixture washeated to 100° C. and kept there for 80 min, in order to distill off thewater.

The mixture was purged three times with N₂. Thereafter, the vessel waschecked for pressure retention, 0.5 bar gauge (1.5 bar absolute) wasset, the mixture was heated to 127° C. and then the pressure was set to3 bar absolute. 57.7 g (1.311 mol) of EO were metered in at 127° C.;p_(max) was 6 bar absolute. After waiting for 30 min for establishmentof constant pressure, the mixture was decompressed to 4.0 bar absolute.

604.2 g (8.392 mol) of BuO were metered in at 127° C.; p_(max) was 6 barabsolute. One intermediate decompression was necessary owing toincreasing fill level. The BuO metering was stopped, and the mixture wasleft to react for 1 h until pressure was constant and decompressed to4.0 bar absolute. Thereafter, the metered addition of BuO was continued.P_(max) was still 6 bar (first decompression after 505 g of BuO, totalBuO metering time 11 h incl. decompression break). After meteredaddition of BuO had ended, the reaction was allowed to continue for 6 hat 127° C. It was decompressed to 4 bar absolute.

Thereafter 80.8 g (1.836 mol) of EO were metered at 127° C.; p_(max) was6 bar absolute. After metered addition of EO had ended, the reaction wasallowed to continue for 4 h. The mixture was cooled to 100° C., andresidual oxide was drawn off until the pressure was below 10 mbar for atleast 10 min. About 1400 ppm of volatile components were removed. Then0.5% water was added at 120° C. and volatiles were subsequently drawnoff until the pressure was below 10 mbar for at least 10 min. The vacuumwas broken with N₂ and 100 ppm of BHT were added. The transfer waseffected at 80° C. under N₂.

The analysis (mass spectrum, GPC, 1H NMR in CDCl₃, 1H NMR in MeOD)confirmed the structure.

I-b Preparation of the Copolymers Based on Monomers (M2-M30) Example C1General Preparation of a Copolymer from 2% by Weight of Monomer M, 50%by Weight of Acrylamide and 48% by Weight of2-Acrylamido-2-Methylpropanesulfonic Acid

A plastic bucket with a magnetic stirrer, pH meter and thermometer wasinitially charged with 121.2 g of a 50% aqueous solution of NaATBS(2-acrylamido-2-methylpropanesulfonic acid, Na salt), followed bysuccessive addition of 155 g of distilled water, 0.6 g of a defoamer(Surfynol® DF-58), 0.2 g of a silicone defoamer (Baysilon® EN), 2.3 g ofmonomer M, 114.4 g of a 50% aqueous solution of acrylamide, 1.2 g ofpentasodium diethylenetriaminepentaacetate (complexing agent, as a 5%aqueous solution) and 2.4 g of a nonionic surfactant (isotridecanol,alkoxylated with 15 units of ethylene oxide).

After adjusting the pH with a 20% or 2% sulfuric acid solution to avalue of 6 and adding the rest of the water, the monomer solution wasadjusted to the start temperature of 5° C. The total amount of the waterwas such that—after the polymerization—a solids concentration of approx.30 to 36% by weight was attained. The solution was transferred into athermos flask, a temperature sensor was provided for temperaturerecording and the solution was purged with N₂ for 30 minutes. Thepolymerization was subsequently initiated by addition of 1.6 ml of a 10%aqueous solution of a water-soluble cationic azo initiator2,2′-azobis(2-amidinopropane)dihydrochloride (Wako V-50), 0.12 ml of a1% aqueous solution of tert-butyl hydroperoxide and 0.24 ml of a 1%sodium sulfite solution. After the initiators had been added, thetemperature rose to approx. 80° C. within 15 to 30 min. After 30 min,the reaction vessel was placed in a drying cabinet at approx. 80° C. forapprox. 2 h to complete the polymerization. The total polymerizationtime was about 2 h to 2.5 h.

A gel block was obtained, which, after the polymerization had ended, wascomminuted with a meat grinder. The gel granules thus obtained weredried in a fluidized bed drier at 55° C. for two hours. Hard whitegranules were obtained, which were converted to a pulverulent state bymeans of a centrifugal mill. A copolymer was obtained with aweight-average molecular weight of about 1 000 000 g/mol to 30 000 000g/mol.

Example C2 Copolymer Based on Monomer M2

The copolymer was obtained according to the above general preparationmethod by using monomer 2 from comparative example M2.

Examples C3 to C30

Copolymers C3 to C30 were prepared by the above general method by usingthe respective monomers M3 to M30.

PART II: PERFORMANCE TESTS

The resulting copolymers based on the above monomers were used toconduct the tests which follow, in order to assess the suitabilitythereof for tertiary mineral oil production.

Description of the Test Methods a) Determination of Solubility

The copolymers were dissolved in synthetic seawater to DIN 50900 (saltcontent 35 g/l) so as to give a polymer concentration of 2000 ppm: 0.5 gof the respective copolymer was stirred in 249 g of synthetic seawater(DIN 50900) for 24 h until complete dissolution (the precision glassstirrer used should preferably be a paddle stirrer; the polymer wasscattered gradually into the vortex which forms).

b) Determination of Viscosity

The viscosities of the abovementioned copolymer solutions weredetermined using a Haake rheometer with double gap geometry at 7 Hz and60° C. After approx. 5 min, a plateau value was established for theviscosity, which was read off. Very good values were considered to beviscosities greater than or equal to 150 mPas (2000 ppm of copolymer insynthetic seawater at 600° C. and 7 Hz). Good values were considered tobe viscosities greater of 120 mPas to 149 mPas. Moderate viscosityvalues were considered to be from 80 to 119 mPas. Viscosities of lessthan 80 mPas were considered to be poor.

c) Determination of Filterability

Prior to the actual filtration test, the polymer solution was filteredthrough a 200 μm Retsch sieve to determine the gel content thereof.

The filtration test to determine the MPFR value—the ratio of the flowrate of the first quarter to that of the fourth quarter is called the“Millipore filter ratio” (MPFR)—was conducted by means of a Sartorius16249 pressure filtration cell (filter diameter 47 mm) and an Isoporepolycarbonate membrane filter (diameter 47 mm, pore size 3 μm) at roomtemperature and 1 bar gauge. 210-220 g of polymer solution were used. Inthe test, at least 180 g of filtrate were to pass through within 30minutes. Good values were considered to be MPFR of less than or equal to1.3. If they are between 1.3 and 1.6, filterability was considered to bemoderate. If less than 30 g of filtrate passed through, the sample wasconsidered to be unfilterable.

d) Determination of the Gel Content

1 g of the respective copolymer from preparation examples 2-30 wasstirred in 249 g of synthetic seawater to DIN 50900 (salt content 35g/l) until complete dissolution for 24 h. Subsequently, the solution wasfiltered through a sieve of mesh size 200 μm and the volume of theresidue remaining on the sieve was measured. The value obtainedcorresponds to the gel content.

Test Results:

Gel Example Copolymer Soluble? Viscosity Filterability content 2 C2based on M2 yes good good 0 ml HBVE-22 EO-10.6 PeO (0.4 mol % ofpotassium ions, 4.6 mol % of sodium ions), addition of the PeO at 140°C. to 3.2 bar 3 C3 based on M3 yes good unfilterable 2 ml HBVE-22EO-10.5 PeO (0.4 mol % of potassium ions, 3.3 mol % of sodium ions),addition of the PeO at 140° C. to 2.1 bar 4 C4 based on M4 yes good good0 ml HBVE-22 EO-10 PeO (0.4 mol % of potassium ions, 4.6 mol % of sodiumions), addition of the PeO at 127° C. to 2.1 bar 5 C5 based on M5 yesgood unfilterable 12 ml HBVE-22 EO-11 PeO (0.4 mol % of potassium ions,4.6 mol % of sodium ions), addition of the PeO at 127° C. to 2.1 bar 6C6 based on M6 yes good good 0 ml HBVE-24.5 EO-11 PeO (0.4 mol % ofpotassium ions, 4.6 mol % of sodium ions), addition of the PeO at 127°C. to 2.1 bar 7 C7 based on M7 yes good good 0 ml HBVE-24.5 EO-10 PeO(0.4 mol % of potassium ions, 4.6 mol % of sodium ions), addition of thePeO at 127° C. to 2.1 bar 8 C8 based on M8 yes good moderate 0-1 mlHBVE-24.5 EO-10 PeO (0.9 mol % of potassium ions, 4.1 mol % of sodiumions), addition of the PEO at 127° C. to 2.1 bar 9 C9 based on M9 yesgood unfilterable 3 ml HBVE-24.5 EO-10 PeO (1.5 mol % of potassium ions,4.6 mol % of sodium ions), addition of the PeO at 127° C. to 2.1 bar 10C10 based on M10 yes good good 0 ml HBVE-24.5 EO-10 PeO (0.4 mol % ofpotassium ions, 5.5 mol % of sodium ions), addition of the PeO at 127°C. to 2.1 bar 11 C11 based on M11 yes good good 0 ml HBVE-24.5 EO-PeO(0.4 mol % of potassium ions, 5.5 mol % of sodium ions), addition of thePeO at 127° C. to 2.1 bar 12 C12 based on M12 yes good unfilterable 48ml HBVE-24.5 EO-PeO (5.8 mol % of potassium ions), addition of the PeOat 127° C. to 2.1 bar 13 C13 based on M13 yes good moderate 0-1 mlHBVE-24.5 EO-8 PeO (0.4 mol % of potassium ions, 4.6 mol % of sodiumions), addition of the PeO at 127° C. to 2.1 bar 14 C14 based on M14 yesgood moderate 0-1 ml HBVE-26.5 EQ-10 PeO (0.4 mol % of potassium ions,5.5 mol % of sodium ions), addition of the PeO at 127° C. to 2.1 bar 15C15 based on M15 yes good good 0 ml HBVE-24.5 EO-10 PeO (0.4 mol % ofpotassium ions, 5.5 mol % of sodium ions), addition of the PeO at 122°C. to 2.1 bar 16 C16 based on M16 yes good good 0 ml HBVE-24.5 EO-10 PeO(0.4 mol % of potassium ions, 5.5 mol % of sodium ions), addition of thePEO at 132° C. to 2.1 bar 17 C17 based on M17 yes poor good 0 mlHBVE-24.5 EO-10 BuO (0.4 mol % of potassium ions, 5.5 mol % of sodiumions), addition of the BuO at 127° C. to 2.1 bar 18 C18 based on M18 yespoor good 0 ml HBVE-24.5 EO-12 BuO (0.4 mol % of potassium ions, 5.5 mol% of sodium ions), addition of the BuO at 127° C. to 2.1 bar 19 C19based on M19 yes good good 0 ml HBVE-24.5 EO-14 BuO (0.4 mol % ofpotassium ions, 5.5 mol % of sodium ions), addition of the BuO at 127°C. to 2.1 bar 20 C20 based on M20 yes good good 0 ml HBVE-24.5 EO-16 BuO(0.4 mol % of potassium ions, 5.5 mol % of sodium ions), addition of theBuO at 127° C. to 2.1 bar 21 C21 based on M21 yes good unfilterable 2 mlHBVE-24.5 EO-18 BuO (0.4 mol % of potassium ions, 5.5 mol % of sodiumions), addition of the BuO at 127° C. to 2.1 bar 22 C22 based on M22 yesgood unfilterable 5-10 ml HBVE-24.5 EO-16 BuO (5.8 mol % of potassiumions), addition of the BuO at 127° C. to 3.1 bar 23 C23 based on M23 yesgood good 0 ml HBVE-24.5 EO-16 BuO (0.4 mol % potassium ions, 11 mol %sodium ions), addition of the BuO at 127° C. to 3.1 bar 24 C24 based onM24 yes very good 0 ml HBVE-23 EO,-17 BuO-2.5 EO good (0.4 mol %potassium ions , 5.5 mol % sodium ions), addition of the BuO at 127° C.to 3.1 bar 25 C25 based on M25 yes very good 0 ml HBVE-24.5 EO-16BuO-3.5 EO good (0.4 mol % potassium ions, 5.5 mol % sodium ions),addition of the BuO at 127° C. to 3.1 bar 26 C26 based on M26 yes verygood 0 ml HBVE-24.5 EO-16 BuO-5 EO good (0.4 mol % potassium ions, 5.5mol % sodium ions), addition of the BuO at 127° C. to 3.1 bar 27 C27based on M27 yes moderate good 0 ml HBVE-24.5 EO-10 BuO-3.5 EO (0.4 mol% potassium ions, 5.5 mol % sodium ions), addition of the BuO at 127° C.to 3.1 bar 28 C28 based on M28 yes moderate good 0 ml HBVE-24.5 EO-5BuO-3.5 EO (0.4 mol % potassium ions, 5.5 mol % sodium ions), additionof the BuO at 127° C. to 3.1 bar 29 C29 based on M29 HBVE-24.5 EO-22BuO-3.5 EO yes very very 0 ml (0.4 mol % potassium ions, good good 5.5mol % sodium ions), addition of the BuO at 127° C. to 3.1 bar 30 C30based on M30 HBVE-24.5 EO-16 BuO-3.5 EO yes very good 0 ml (0.4 mol %potassium ions, good 5.5 mol % sodium ions), addition of the BuO at 127°C. at 4 to 6 bar

Examples 2 and 3 show that the pressure window for the PeO metering at140° C. has a great influence on the product quality. A larger pressurewindow enables rapid metering and a short cycle time (2 h for PeO). If,however, the pressure window required by the safety specifications isobserved, as in example 3, the reaction is prolonged (2 days for PeO).As a result of the high temperature, there are side reactions andformation of crosslinkers, the effect of which is that the latercopolymerization forms a thickening copolymer which is no longerfilterable, and this is no longer employable for uses in a porous matrix(for example mineral oil-bearing rock strata, thickeners in mineral oilproduction).

Example 4 shows that lowering the reaction temperature while maintainingthe small pressure window can produce copolymers free of crosslinkers.As can be seen in the examples, the concentration of potassium ions isof central significance. As examples 9 and 12 show, above 0.9 mol % ofpotassium ions, the polymer is no longer filterable in spite oftemperatures of 127° C. in the PeO metering. A potassium ionconcentration greater than 0.9 mol % apparently leads to the formationof crosslinking compounds which lead to a copolymer which is no longerfilterable. In addition, the exact content of sodium ion catalystappears also to play an important role.

Surprisingly, it is additionally observed that thehydrophilic/hydrophobic ratio of the monomer is also of greatsignificance. In spite of crosslinker-free operation, the copolymeraccording to example 5 has somewhat poorer filterability than copolymersbased on monomers with only 1 eq of PeO less (example 4). If monomerswith 24.5 units of EO are used, the variation in the PeO units has noinfluence on the filterability of the copolymers (comparison of examples6 and 7 and comparison of examples 10 and 11). The specific selection ofa hydrophilic/hydrophobic ratio, i.e. ratio of EO and PeO units, led tosurprising robustness of the process. In examples 10 and 11 (24.5 EOunits), no variation in the PeO content was perceptible. This gives goodstability for industrial scale production, where variations of less than1 eq of alkylene oxide are not easy to guarantee. Deviations in processand structure are thus much better tolerated in the later copolymersynthesis or application.

A similar picture is found in the case of copolymers based on monomerswith terminal BuO groups. A comparison of examples 20 and 22 shows that,in the case of preparation of copolymers based on monomers with terminalBuO groups too, a concentration of potassium ions of less than 0.9 mol %surprisingly leads to improved copolymers. Excessively high values forpotassium ions in the copolymer lead to unfilterable structures.

Examples 19 and 20 show that optimal product properties (goodviscosities and good filterability) can be achieved especially at abutoxylation level above 12 and below 18. A comparison of the resultsrelating to monomers with terminal PeO groups and relating to monomerswith terminal BuO groups has additionally shown that the total number ofcarbon atoms in the side chains of the monomers, especially in theterminal alkylene oxide blocks, is of crucial significance for theproperty of the resulting copolymers. For example, the total number ofcarbon atoms in the side chains of the terminal alkylene oxide blockfrom examples 19 and 20 (total of 28 to 32 carbon atoms in side chains)coincides with the total number range in examples 6, 10 and 11 (total of27 to 33 carbon atoms in side chains) relating to monomers with terminalPeO groups. Other butoxylation levels as in examples 17, 18 and 21 leadto properties of the monomer which are no longer optimal in all ranges.

Further, it has been shown that monomers with BuO blocks, in particularwith blocks having 16 to 22 BuO units, can advantageously be modifiedwith an terminal EO block. Thus, copolymers with very good viscosityproperties and good filterability can be obtained (examples 24 to 26 and29). Contrary, it seems that the introduction of an terminal EO block inmonomers having an BuO block with less than 12 BuO units do not resultin an advantageous effect (examples 27 and 28).

Example 23 shows that the concentration of sodium ions can be up to atleast 11 mol % during the addition of butylene oxide.

Example 30 shows that the addition of butylene oxide can alsoadvantageously be carried out at a pressure in the range of 4 to 6 bar.

1.-20. (canceled)
 21. A water-soluble hydrophobically associatingcopolymer comprising (a) 0.1 to 20% by weight of at least onehydrophobically associating monomer (a), and (b) 25 to 99.9% by weightof at least one hydrophilic monomer (b) other than monomer (a), with useof at least one further, nonpolymerizable surface-active component (c)in the course of synthesis thereof, prior to the initiation of thepolymerization reaction, where the stated amounts are each based on thetotal amount of all monomers in the copolymer, at least one of themonomers (a) being a monomer of the general formula (I)H₂C═C(R¹)—R²—O—(—CH₂—CH₂—O—)_(k)—(—CH₂—CH(R³)—O—)_(l)—(—CH₂—CH₂—O—)_(m)—R⁴  (I)where the —(—CH₂—CH₂—O—)_(k), —(—CH₂—CH(R³)—O—)_(l) and optionally—(—CH₂—CH₂—O—)_(m) units are arranged in block structure in the sequenceshown in formula (I) and the radicals and indices are each defined asfollows: k: is a number from 15 to 35; l: is a number from 5 to 25; m:is a number from 0 to 15; R¹: is H or methyl; R²: is independently asingle bond or a divalent linking group selected from the groupconsisting of —(C_(n)H_(2n))— and —O—(C_(n′)H_(2n′))—, where n is anatural number from 1 to 6 and n′ is a natural number from 2 to 6; R³:is independently a hydrocarbyl radical having at least 2 carbon atoms oran ether group of the general formula —CH₂—O—R^(3′) where R^(3′) is ahydrocarbyl radical having at least 2 carbon atoms; with the provisothat the sum total of the carbon atoms in all hydrocarbyl radicals R³ orR^(3′) is in the range from 15 to 50, R⁴: is independently H or ahydrocarbyl radical having 1 to 4 carbon atoms; and the hydrophobicallyassociating monomer (a) of the general formula (I) is obtained by aprocess comprising the following steps: a) reacting a monoethylenicallyunsaturated alcohol A1 of the general formula (II)H₂C═C(R¹)—R²—OH  (II)  with ethylene oxide,  where the R¹ and R²radicals are each as defined above;  with addition of an alkalinecatalyst C1 comprising KOMe and/or NaOMe to obtain an alkoxylatedalcohol A2; b) reacting the alkoxylated alcohol A2 with at least onealkylene oxide Z of the formula (Z)

 where R³ is as defined above;  with addition of an alkaline catalystC2;  where the concentration of potassium ions in the reaction in stepb) is less than or equal to 0.9 mol %, based on the alcohol A2 used; and where the reaction in step b) is performed at a temperature lessthan or equal to 135° C.,  to obtain an alkoxylated alcohol A3 of theformula (III)H₂C═C(R¹)—R²—O—(—CH₂—CH₂—O—)_(k)—(—CH₂—CH(R³)—O—)_(l)—R⁴  (III)  whereR⁴=H, where the R¹, R² and R³ radicals and the indices k and l are eachas defined above; c) optionally reacting at least a portion of thealkoxylated alcohol A3 with ethylene oxide to obtain an alkoxylatedalcohol A4 corresponding to the monomer (a) of the formula (I) whereR⁴=H and m is greater than 0; d) optionally etherifying the alkoxylatedalcohol A3 and/or A4 with a compoundR₄—X  where R⁴ is as defined above and X is a leaving group, preferablyselected from the group consisting of Cl, Br, I, —O—SO₂—CH₃ (mesylate),—O—SO₂—CF₃ (triflate) and —O—SO₂—OR⁴  to obtain a monomer (a) of theformula (I) where R⁴=hydrocarbyl radical having 1 to 4 carbon atoms. 22.The copolymer according to claim 21, wherein the radicals and indicesare each defined as follows: k: is a number from 23 to 26; l: is anumber from 5 to 25; m: is a number from 0 to 15; R¹: is H or methyl;R²: is independently a single bond or a divalent linking group selectedfrom the group consisting of —(C_(n)H_(2n))— and —O—(C_(n′)H_(2n′))—,where n is a natural number from 1 to 6 and n′ is a natural number from2 to 6; R³: is independently a hydrocarbyl radical having at least 2carbon atoms or an ether group of the general formula —CH₂—O—R^(3′)where R^(3′) is a hydrocarbyl radical having at least 2 carbon atoms;with the proviso that the sum total of the carbon atoms in allhydrocarbyl radicals R³ or R^(3′) is in the range from 15 to 50, R4: isindependently H or a hydrocarbyl radical having 1 to 4 carbon atoms. 23.The copolymer according to claim 21, wherein the radicals and indicesare each defined as follows: k: is a number from 23 to 26; l: is anumber from 8.5 to 17.25; m: is a number from 0 to 15; R¹: is H ormethyl; R²: is independently a single bond or a divalent linking groupselected from the group consisting of —(C_(n)H_(2n))— and—O—(C_(n′)H_(2n′))—, where n is a natural number from 1 to 6 and n′ is anatural number from 2 to 6; R³: is independently a hydrocarbyl radicalhaving at least 2 carbon atoms or an ether group of the general formula—CH₂—O—R^(3′) where R^(3′) is a hydrocarbyl radical having at least 2carbon atoms; with the proviso that the sum total of the carbon atoms inall hydrocarbyl radicals R³ or R^(3′) is in the range from 25.5 to 34.5,R⁴: is independently H or a hydrocarbyl radical having 1 to 4 carbonatoms.
 24. The copolymer according to claim 21, wherein the radicals andindices are each defined as follows: k: is a number from 23 to 26; l: isa number from 12.75 to 17.25; m: is a number from 0 to 15; R¹: is H; R²:is a divalent linking group —O—(C_(n′)H_(2n′))— where n′ is 4; R³: isindependently a hydrocarbyl radical having 2 carbon atoms; R⁴: is H. 25.The copolymer according to claim 21, wherein the radicals and indicesare each defined as follows: k: is a number from 23 to 26; l: is anumber from 8.5 to 11.5; m: is a number from 0 to 15; R¹: is H; R²: is adivalent linking group —O—(C_(n′)H_(2n′))— where n′ is 4; R³: is ahydrocarbyl radical having 3 carbon atoms; R⁴: is H.
 26. The copolymeraccording to claim 21, wherein the monomer (a) of the general formula(I) is a mixture of a monomer (a) of the formula (I) where m=0 and amonomer (a) of the formula (I) where m=1 to
 15. 27. The copolymeraccording to claim 26, wherein the weight ratio of the monomer of theformula (I) where m=0 and the monomer of the formula (I) where m=1 to 15is in the range from 19:1 to 1:19.
 28. The copolymer according to claim21, wherein the concentration of potassium ions in the preparation ofmonomer (a), in the reaction in step b), is 0.01 to 0.5 mol % based onthe alcohol A2 used.
 29. The copolymer according to claim 21, whereinthe preparation of monomer a) involves using a catalyst C2 comprising atleast one basic sodium compound in step b), the concentration of sodiumions in the reaction in step b) being in the range from 3.5 mol % to 12mol %, based on the alcohol A2 used.
 30. The copolymer according toclaim 21, wherein step b) in the preparation of monomer (a) is performedat a pressure in the range from 1 to 3.1 bar and a temperature of 120 to135° C.
 31. The copolymer according to claim 21, wherein R³ is ahydrocarbyl radical having 2 carbon atoms and step b) in the preparationof monomer (a) is performed at a pressure in the range from 1 to 3.1bar; or R³ is a hydrocarbyl radical having at least 3 carbon atoms andstep b) in the preparation of monomer (a) is performed at a pressure of1 to 2.1 bar.
 32. The copolymer according to claim 21, wherein at leastone of the monomers (b) is a monomer comprising acidic groups, theacidic groups being at least one group selected from the group of —COOH,—SO₃H and —PO₃H₂, and salts thereof.
 33. The copolymer according toclaim 21, which comprises at least two different hydrophilic monomers(b) which are at least one uncharged hydrophilic monomer (b1), and atleast one hydrophilic anionic monomer (b2) comprising at least oneacidic group selected from the group consisting of —COOH, —SO₃H and—PO₃H₂ and salts thereof.
 34. The copolymer according to claim 21,comprising (a) 2% by weight of at least one hydrophobically associatingmonomer (a), and (b) 50% by weight of acrylamide as an unchargedhydrophilic monomer (b1), and (c) 48% by weight ofacrylamido-2-methylpropanesulfonic acid (AMPS) as an anionic hydrophilicmonomer (b2), where the stated amounts are each based on the totalamount of all monomers in the copolymer.
 35. The copolymer according toclaim 21, wherein component (c) is at least one nonionic surfactant. 36.A process for preparing a water-soluble, hydrophobically associatingcopolymer according to claim 21, which comprises subjecting at least onehydrophobically associating monomer (a) and at least one hydrophilicmonomer (b) to an aqueous solution polymerization in the presence of atleast one surface-active component (c), the monomer (a) of the generalformula (I) being prepared by a process as described in claim
 21. 37.The process for preparing a copolymer according to claim 36, wherein thesolution polymerization is performed at a pH in the range from 5.0 to7.5.
 38. A method of using the copolymer according to claim 21 in thedevelopment, exploitation and completion of underground mineral oil andnatural gas deposits.
 39. A method for tertiary mineral oil production,comprising injecting an aqueous formulation of the copolymer accordingto claim 21 in a concentration of 0.01 to 5% by weight into a mineraloil deposit through at least one injection well; and withdrawing crudeoil from the deposit through at least one production well.
 40. Themethod according to claim 39, wherein the aqueous formulation of saidcopolymers comprises at least one surfactant.